[OnePlus 6T  ROMs, Kernels, Recoveries, & Other Dev] shaowd:
Same issue here. The phone never makes it past the "phone is restarting" load screen. I managed to dump some logs and I suspect the problem is related to live display and SELinux, as the following log loops.

01-08 06:40:24.050 0 0 E init : Control message: Could not find 'vendor.lineage.livedisplay@2.0::IDisplayModes/default' for ctl.interface_start from pid: 587 (/system/bin/hwservicemanager)
01-08 06:40:24.452 13686 13686 E ProcessState: Binder driver /dev/vndbinder is unavailable. Using /dev/binder instead.
01-08 06:40:24.454 587 587 E SELinux : avc: denied { find } for interface=vendor.display.color::IDisplayColor sid=u:r:hal_livedisplay_sdm845:s0 pid=13686 scontext=u:r:hal_livedisplay_sdm845:s0 tcontext=u:object_r:hal_display_color_hwservice:s0 tclass=hwservice_manager permissive=0
01-08 06:40:24.454 13686 13686 F lineage.livedisplay@2.0-impl-sdm: Failed to initialize SDM backend
01-08 06:40:24.454 13686 13686 F libc : Fatal signal 6 (SIGABRT), code -1 (SI_QUEUE) in tid 13686 (lineage.livedis), pid 13686 (lineage.livedis)
01-08 06:40:24.475 13689 13689 F DEBUG : *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
01-08 06:40:24.475 13689 13689 F DEBUG : Build fingerprint: 'OnePlus/OnePlus6T/OnePlus6T:11/RQ3A.211001.001/1141:userdebug/release-keys'
01-08 06:40:24.475 13689 13689 F DEBUG : Revision: '0'
01-08 06:40:24.475 13689 13689 F DEBUG : ABI: 'arm64'
01-08 06:40:24.476 13689 13689 F DEBUG : Timestamp: 2022-01-08 06:40:24+0800
01-08 06:40:24.476 13689 13689 F DEBUG : pid: 13686, tid: 13686, name: lineage.livedis >>> /system_ext/bin/hw/lineage.livedisplay@2.1-service.oneplus_sdm845 <<<
01-08 06:40:24.476 13689 13689 F DEBUG : uid: 1000
01-08 06:40:24.476 13689 13689 F DEBUG : signal 6 (SIGABRT), code -1 (SI_QUEUE), fault addr --------
01-08 06:40:24.476 13689 13689 F DEBUG : Abort message: 'Failed to initialize SDM backend'
01-08 06:40:24.476 13689 13689 F DEBUG : x0 0000000000000000 x1 0000000000003576 x2 0000000000000006 x3 0000007fea0dccf0
01-08 06:40:24.476 13689 13689 F DEBUG : x4 0000000000000000 x5 0000000000000000 x6 0000000000000000 x7 000000000001ecae
01-08 06:40:24.476 13689 13689 F DEBUG : x8 00000000000000f0 x9 383042ef75125222 x10 0000000000000000 x11 ffffffc0ffffffdf
01-08 06:40:24.476 13689 13689 F DEBUG : x12 0000000000000001 x13 0000000000000021 x14 001a76e5e360b800 x15 0000a09843944e37
01-08 06:40:24.476 13689 13689 F DEBUG : x16 0000007f2ee4bc80 x17 0000007f2ee2dc10 x18 0000007f2fc98000 x19 0000000000003576
01-08 06:40:24.476 13689 13689 F DEBUG : x20 0000000000003576 x21 00000000ffffffff x22 0000007f2f6a4000 x23 0000007f2f6a4000
01-08 06:40:24.476 13689 13689 F DEBUG : x24 0000007f2f6a4000 x25 0000000000000000 x26 0000000000000000 x27 0000000000000000
01-08 06:40:24.476 13689 13689 F DEBUG : x28 0000000000000000 x29 0000007fea0dcd70
01-08 06:40:24.476 13689 13689 F DEBUG : lr 0000007f2ede02a0 sp 0000007fea0dccd0 pc 0000007f2ede02cc pst 0000000000000000
01-08 06:40:24.480 13689 13689 F DEBUG : backtrace:
01-08 06:40:24.480 13689 13689 F DEBUG : #00 pc 000000000004e2cc /apex/com.android.runtime/lib64/bionic/libc.so (abort+164) (BuildId: be9c72fe4db37cd191b589b74d090d13)
01-08 06:40:24.480 13689 13689 F DEBUG : #01 pc 00000000000062b0 /system/lib64/liblog.so (__android_log_default_aborter+12) (BuildId: b5b2ed9d2859e7c956635d8bdb685c6f)
01-08 06:40:24.480 13689 13689 F DEBUG : #02 pc 0000000000012fa4 /system/lib64/libbase.so (android::base::LogMessage::~LogMessage()+320) (BuildId: 5ddeb405cbf5aa6e6ee96e6f09211cdd)
01-08 06:40:24.480 13689 13689 F DEBUG : #03 pc 000000000000813c /system/system_ext/bin/hw/lineage.livedisplay@2.1-service.oneplus_sdm845 (vendor::lineage::livedisplay::V2_0::sdm::SDMController::SDMController()+1100) (BuildId: 9d3fd6920828a68a9353e2786aa32f70)
01-08 06:40:24.480 13689 13689 F DEBUG : #04 pc 000000000000d114 /system/system_ext/bin/hw/lineage.livedisplay@2.1-service.oneplus_sdm845 (main+152) (BuildId: 9d3fd6920828a68a9353e2786aa32f70)
01-08 06:40:24.480 13689 13689 F DEBUG : #05 pc 000000000004988c /apex/com.android.runtime/lib64/bionic/libc.so (__libc_init+108) (BuildId: be9c72fe4db37cd191b589b74d090d13)
01-08 06:40:24.500 741 741 E tombstoned: Tombstone written to: /data/tombstones/tombstone_38
01-08 06:40:24.501 0 0 E init : updatable process 'livedisplay-hal-2-1' exited 4 times before boot completed

A similar issue is also reported in this lineage build

In my test it seems to only affects the Pixel Experience Plus