[Moto G5S  Questions & Answers] TwoPointZero:
Sorry, I didn't read all the info you posted. Just suggested you try booting with no SIM or SD card inside.

Looking at the LMSA you posted, mine said prior to flashing:

2020-08-05 15:47:42 [11] [INFO] Device:[Device info[id:ZY******, mn:XT1805,ps:eek:ffline,ss:eek:ffline]] disconnected
2020-08-05 15:47:45 [25] [INFO] Current_SoftStatusChanged - get match params by model name: XT1805
2020-08-05 15:47:46 [25] [INFO] Work - Takes 610 milliseconds, request url[https://lmsa.prod.cloud.lenovo.com/Interface/rescueDevice/getRomMatchParams.jhtml]
2020-08-05 15:47:46 [25] [INFO] Current_SoftStatusChanged - match rescue resource params: {"blurVersion":"Blur_Version.26.11.30.sanders.retail.en.US","fingerPrint":"motorola/sanders_n/sanders_n:7.1.1/NPS26.116-26/30:user/release-keys","fsgVersion.qcom":"SANDERS_EMEADSDS_CUST","roCarrier":"reteu"}
2020-08-05 15:47:48 [25] [INFO] Work - Takes 1389 milliseconds, request url[https://lmsa.prod.cloud.lenovo.com/Interface/rescueDevice/getNewResource.jhtml]
2020-08-05 15:48:13 [16] [INFO] <Start>b__42_0 - Downloading file SANDERS_OPS28.65_36_14_cid50_subsidy_DEFAULT_regulatory_DEFAULT_CFC.xml.zip - try 1
2020-08-05 15:48:14 [6 ] [INFO] <Start>b__42_0 - Downloading file Fastboot_Mot_V1.zip - try 1
2020-08-05 15:48:15 [6 ] [INFO] <Extractor>b__2 - C:\ProgramData\LMSA\Download\ToolFiles\Fastboot_Mot_V1.zip already extractor finished
2020-08-05 15:57:52 [16] [INFO] <Extractor>b__2 - C:\ProgramData\LMSA\Download\RomFiles\SANDERS_OPS28.65_36_14_cid50_subsidy_DEFAULT_regulatory_DEFAULT_CFC.xml.zip already extractor finished
2020-08-05 15:57:53 [29] [INFO] Work - Takes 774 milliseconds, request url[https://lmsa.prod.cloud.lenovo.com/Interface/dataCollection/romDownloadInfo.jhtml]
2020-08-05 15:59:41 [1 ] [INFO] Run - ************Running [LMSA_Recovery] use case start***********
2020-08-05 15:59:41 [28] [INFO] Run - Running Recipe FastBoot Devices
2020-08-05 15:59:41 [28] [INFO] Run - [LMSA_Recovery] Running step 'Waiting to enter Fastboot Flash Mode (WaitConnectByFastboot)'
2020-08-05 15:59:41 [28] [INFO] AddResult - [LMSA_Recovery] Step 'Waiting to enter Fastboot Flash Mode' result 'Passed'
2020-08-05 15:59:41 [28] [INFO] Run - [LMSA_Recovery] Running step 'Waiting (Sleep)'
2020-08-05 15:59:46 [28] [INFO] AddResult - [LMSA_Recovery] Step 'Waiting' result 'Passed'
2020-08-05 15:59:46 [28] [INFO] Run - [LMSA_Recovery] Running step 'Read Device Mode (ReadDeviceMode)'
2020-08-05 15:59:46 [28] [INFO] AddResult - [LMSA_Recovery] Step 'Read Device Mode' result 'Passed'
2020-08-05 15:59:46 [28] [INFO] Run - [LMSA_Recovery] Running step 'Connect to Android Device (ADBConnect)'
2020-08-05 15:59:46 [28] [INFO] AddResult - [LMSA_Recovery] Step 'Connect to Android Device' result 'Skipped'
2020-08-05 15:59:46 [28] [INFO] Run - [LMSA_Recovery] Running step 'Switch to Fastboot Mode (AndroidShell)'
2020-08-05 15:59:46 [28] [INFO] AddResult - [LMSA_Recovery] Step 'Switch to Fastboot Mode' result 'Skipped'
2020-08-05 15:59:46 [28] [INFO] Run - [LMSA_Recovery] Running step 'Wait for Fastboot Mode (Sleep)'
2020-08-05 15:59:46 [28] [INFO] AddResult - [LMSA_Recovery] Step 'Wait for Fastboot Mode' result 'Skipped'
2020-08-05 15:59:46 [28] [INFO] Run - [LMSA_Recovery] Running step 'Check if image matches the connected device (FastbootDeviceMatchCheck)'
2020-08-05 15:59:46 [28] [INFO] ReadFastbootDeviceModelName - [LMSA_Recovery] use tool: C:\ProgramData\LMSA\Download\ToolFiles\Fastboot_Mot_V1\Fastboot_Mot_V1\fastboot.exe
2020-08-05 15:59:46 [28] [INFO] AddResult - [LMSA_Recovery] Step 'Check if image matches the connected device' result 'Passed'
2020-08-05 15:59:46 [28] [INFO] Run - [LMSA_Recovery] Running step 'Load Flash Files (LoadFiles)'
2020-08-05 15:59:46 [28] [INFO] RunStep - [LMSA_Recovery] loadfile, xmlFile=C:\ProgramData\LMSA\Download\RomFiles\SANDERS_OPS28.65_36_14_cid50_subsidy_DEFAULT_regulatory_DEFAULT_CFC.xml\flashfile.xml
2020-08-05 15:59:46 [28] [INFO] AddResult - [LMSA_Recovery] Step 'Load Flash Files' result 'Passed'
(...)flashing stuff

therefore the en.US part is confusing but expected. Your detection sequence is showing "fsgVersion.qcom":null, as you said it cannot read the baseband version

Is flashing fsg a huge no-no for you? Is unlocking the BL considered tampering with the device as far as the investigation is concerned?

According to others the IMEI is stored in the persist partition (which should by no means be exported from a phone to another) since Moto G5 and modemst1 modemst2 can be regenerated from persist if they've been erased.

If that is an acceptable 'risk' to you, I would flash fsg.mbn as suggested by sd_shadow.

EDIT: I realized you've done just that in your Aug 2nd reply

Was there any specific output shown for the fastboot commands?