[LG G5 ROMs, Kernels, Recoveries, & Other Developme] nausikaa:
RS988, 16.1 official, GSM/WCDMA/LTE.

The above output is from adb logcat.

You're right, I just had to wait and the network came up! Selecting my network gives:

$ adb logcat -b radio
...
03-20 16:39:36.888 2269 2407 D DC-C-1 : DcActivatingState onSetupConnectionCompleted result=ERROR_DATA_SERVICE_SPECIFIC_ERROR SetupResult.mFailCause=50 dc={DC-C-1: State=DcActivatingState mApnSetting=[ApnSettingV7] TELUS SP, 1067, 30
2220, sp.telus.com, , http://aliasredirect.net/proxy/mmsc, mmscproxy.mobility.ca, 8799, null, -1, mms | supl | hipri | default | ia, IPV6, IP, true, 0, false, 0, 0, 0, 0, gid, 5455, false, 0, 0, -1, -1 RefCount=1 mCid=-1 mCreateTime=-1 m
LastastFailTime=-1 mLastFailCause=0 mTag=24 mLinkProperties={LinkAddresses: [ ] DnsAddresses: [ ] Domains: null MTU: 0 TcpBufferSizes: 2097152,4194304,8388608,262144,524288,1048576 Routes: [ ]} linkCapabilities=[ Transports: CELLULAR Cap
abilities: MMS&SUPL&IA&INTERNET&NOT_RESTRICTED&TRUSTED&NOT_VPN&NOT_ROAMING&NOT_CONGESTED&NOT_SUSPENDED LinkUpBandwidth>=15000Kbps LinkDnBandwidth>=30000Kbps Specifier: <TelephonyNetworkSpecifier [mSubId = 1]> AdministratorUids: [] Reques
torUid: -1 RequestorPackageName: null] mRestrictedNetworkOverride=false mApnContexts={{mApnType=default mState=CONNECTING mWaitingApns={[[ApnSettingV7] TELUS SP, 1067, 302220, sp.telus.com, , http://aliasredirect.net/proxy/mmsc, mmscprox
y.mobility.ca, 8799, null, -1, mms | supl | hipri | default | ia, IPV6, IP, true, 0, false, 0, 0, 0, 0, gid, 5455, false, 0, 0, -1, -1] priority=0} mApnSetting={[ApnSettingV7] TELUS SP, 1067, 302220, sp.telus.com, , http://aliasredirect.
net/proxy/mmsc, mmscproxy.mobility.ca, 8799, null, -1, mms | supl | hipri | default | ia, IPV6, IP, true, 0, false, 0, 0, 0, 0, gid, 5455, false, 0, 0, -1, -1} mReason=nwTypeChanged mDataEnabled=true}={mTag=24 mApnContext={mApnType=defau
lt mState=CONNECTING mWaitingApns={[[ApnSettingV7] TELUS SP, 1067, 302220, sp.telus.com, , http://aliasredirect.net/proxy/mmsc, mmscproxy.mobility.ca, 8799, null, -1, mms | supl | hipri | default | ia, IPV6, IP, true, 0, false, 0, 0, 0,
0, gid, 5455, false, 0, 0, -1, -1] priority=0} mApnSetting={[ApnSettingV7] TELUS SP, 1067, 302220, sp.telus.com, , http://aliasredirect.net/proxy/mmsc, mmscproxy.mobility.ca, 8799, null, -1, mms | supl | hipri | default | ia, IPV6, IP, t
rue, 0, false, 0, 0, 0, 0, gid, 5455, false, 0, 0, -1, -1} mReason=nwTypeChanged mDataEnabled=true} mProfileId=-1 mRat=14 mOnCompletedMsg={what=0x42000 when=-1h10m26s433ms obj=Pair{{mApnType=default mState=CONNECTING mWaitingApns={[[ApnS
ettingV7] TELUS SP, 1067, 302220, sp.telus.com, , http://aliasredirect.net/proxy/mmsc, mmscproxy.mobility.ca, 8799, null, -1, mms | supl | hipri | default | ia, IPV6, IP, true, 0, false, 0, 0, 0, 0, gid, 5455, false, 0, 0, -1, -1] priori
ty=0} mApnSetting={[ApnSettingV7] TELUS SP, 1067, 302220, sp.telus.com, , http://aliasredirect.net/proxy/mmsc, mmscproxy.mobility.ca, 8799, null, -1, mms | supl | hipri | default | ia, IPV6, IP, true, 0, false, 0, 0, 0, 0, gid, 5455, fal
se, 0, 0, -1, -1} mReason=nwTypeChanged mDataEnabled=true} 12} target=Handler (com.android.internal.telephony.dataconnection.DcTracker) {7a96f65} replyTo=null} mRequestType=NORMAL mSubId=1 mIsPreferredApn=true}}}
03-20 16:39:36.889 2269 2407 D DC-C-1 : No suggested retry delay.
03-20 16:39:36.902 2269 2407 D DC-C-1 : DcActivatingState: ERROR_DATA_SERVICE_SPECIFIC_ERROR delay=-2 result=ERROR_DATA_SERVICE_SPECIFIC_ERROR SetupResult.mFailCause=50 result.isRadioRestartFailure=false isPermanentFailure=true
03-20 16:39:36.903 2269 2407 D DC-C-1 : DcInactiveState: setEnterNotificationParams cp,cause
03-20 16:39:36.903 2269 2407 D DC-C-1 : DcInactiveState: enter() mTag=25
03-20 16:39:36.904 2269 2407 D DC-C-1 : DcInactiveState: enter notifyConnectCompleted +ALL failCause=50
03-20 16:39:36.905 2269 2407 D DC-C-1 : notifyConnectCompleted at 1616272776904 cause=50 connectionCompletedMsg={what=0x42000 when=-1h10m26s450ms arg1=-1 arg2=1 obj=android.os.AsyncResult@5b698b4 target=Handler (com.android.internal.t
elephony.dataconnection.DcTracker) {7a96f65} replyTo=null}
03-20 16:39:36.905 2269 2407 D DC-C-1 : Send to all. {mApnType=default mState=CONNECTING mWaitingApns={[[ApnSettingV7] TELUS SP, 1067, 302220, sp.telus.com, , http://aliasredirect.net/proxy/mmsc, mmscproxy.mobility.ca, 8799, null, -1,
mms | supl | hipri | default | ia, IPV6, IP, true, 0, false, 0, 0, 0, 0, gid, 5455, false, 0, 0, -1, -1] priority=0} mApnSetting={[ApnSettingV7] TELUS SP, 1067, 302220, sp.telus.com, , http://aliasredirect.net/proxy/mmsc, mmscproxy.mobi
lity.ca, 8799, null, -1, mms | supl | hipri | default | ia, IPV6, IP, true, 0, false, 0, 0, 0, 0, gid, 5455, false, 0, 0, -1, -1} mReason=nwTypeChanged mDataEnabled=true} ONLY_IPV4_ALLOWED
03-20 16:39:36.906 2269 2269 D DCT-C-0 : onDataSetupComplete: error apn=sp.telus.com, cause=50, requestType=NORMAL
03-20 16:39:36.921 2269 2407 D Dcc-C-0 : removeActiveDcByCid removedDc=null dc={DC-C-1: State=DcInactiveState mApnSetting=[ApnSettingV7] TELUS SP, 1067, 302220, sp.telus.com, , http://aliasredirect.net/proxy/mmsc, mmscproxy.mobility.ca
, 8799, null, -1, mms | supl | hipri | default | ia, IPV6, IP, true, 0, false, 0, 0, 0, 0, gid, 5455, false, 0, 0, -1, -1 RefCount=1 mCid=-1 mCreateTime=-1 mLastastFailTime=1616272776904 mLastFailCause=50 mTag=25 mLinkProperties={LinkAdd
resses: [ ] DnsAddresses: [ ] Domains: null MTU: 0 TcpBufferSizes: 2097152,4194304,8388608,262144,524288,1048576 Routes: [ ]} linkCapabilities=[ Transports: CELLULAR Capabilities: MMS&SUPL&IA&INTERNET&NOT_RESTRICTED&TRUSTED&NOT_VPN&NOT_R
OAMING&NOT_CONGESTED&NOT_SUSPENDED LinkUpBandwidth>=15000Kbps LinkDnBandwidth>=30000Kbps Specifier: <TelephonyNetworkSpecifier [mSubId = 1]> AdministratorUids: [] RequestorUid: -1 RequestorPackageName: null] mRestrictedNetworkOverride=fa
lse mApnContexts={{mApnType=default mState=CONNECTING mWaitingApns={[[ApnSettingV7] TELUS SP, 1067, 302220, sp.telus.com, , http://aliasredirect.net/proxy/mmsc, mmscproxy.mobility.ca, 8799, null, -1, mms | supl | hipri | default | ia, IP
V6, IP, true, 0, false, 0, 0, 0, 0, gid, 5455, false, 0, 0, -1, -1] priority=0} mApnSetting={[ApnSettingV7] TELUS SP, 1067, 302220, sp.telus.com, , http://aliasredirect.net/proxy/mmsc, mmscproxy.mobility.ca, 8799, null, -1, mms | supl |
hipri | default | ia, IPV6, IP, true, 0, false, 0, 0, 0, 0, gid, 5455, false, 0, 0, -1, -1} mReason=nwTypeChanged mDataEnabled=true}={mTag=24 mApnContext={mApnType=default mState=CONNECTING mWaitingApns={[[ApnSettingV7] TELUS SP, 1067, 3
02220, sp.telus.com, , http://aliasredirect.net/proxy/mmsc, mmscproxy.mobility.ca, 8799, null, -1, mms | supl | hipri | default | ia, IPV6, IP, true, 0, false, 0, 0, 0, 0, gid, 5455, false, 0, 0, -1, -1] priority=0} mApnSetting={[ApnSett
ingV7] TELUS SP, 1067, 302220, sp.telus.com, , http://aliasredirect.net/proxy/mmsc, mmscproxy.mobility.ca, 8799, null, -1, mms | supl | hipri | default | ia, IPV6, IP, true, 0, false, 0, 0, 0, 0, gid, 5455, false, 0, 0, -1, -1} mReason=n
wTypeChanged mDataEnabled=true} mProfileId=-1 mRat=14 mOnCompletedMsg=null mRequestType=NORMAL mSubId=1 mIsPreferredApn=true}}}
03-20 16:39:36.921 2269 2407 D DC-C-1 : clearSettings
03-20 16:39:36.924 2269 2269 D DCT-C-0 : cause = 50, mark apn as permanent failed. apn = [ApnSettingV7] TELUS SP, 1067, 302220, sp.telus.com, , http://aliasredirect.net/proxy/mmsc, mmscproxy.mobility.ca, 8799, null, -1, mms | supl | hi
pri | default | ia, IPV6, IP, true, 0, false, 0, 0, 0, 0, gid, 5455, false, 0, 0, -1, -1
03-20 16:39:36.925 2269 2269 D RetryManager: [default] All APNs have permanently failed.
...

I can try reflashing soon.