Those are the ones! 
I see the server startup
Apr 16, 2021 15:55:10.925 [0x7f387219c700] INFO - Plex Media Server v1.22.2.4282-a97b03fad - QNAP TS-453Be x86_64 - build: linux-x86_64 qnap - GMT -04:00
Apr 16, 2021 15:55:10.926 [0x7f387219c700] INFO - Linux version: QTS 4.5.2.1594, language: en-US
Apr 16, 2021 15:55:10.926 [0x7f387219c700] INFO - Processor Intel(R) Celeron(R) CPU J3455 @ 1.50GHz
Apr 16, 2021 15:55:10.926 [0x7f387219c700] INFO - ./Plex Media Server
Apr 16, 2021 15:55:10.926 [0x7f387bc75780] DEBUG - BPQ: [Idle] -> [Starting]
Apr 16, 2021 15:55:10.927 [0x7f387bc75780] DEBUG - FeatureManager: Using cached data for features list
Apr 16, 2021 15:55:10.949 [0x7f387bc75780] DEBUG - Opening 20 database sessions to library (com.plexapp.plugins.library), SQLite 3.26.0, threadsafe=1
Apr 16, 2021 15:55:11.032 [0x7f387bc75780] DEBUG - Running migrations. (EPG 0)
Apr 16, 2021 15:55:11.067 [0x7f387bc75780] DEBUG - ChangestampAllocator: initialized to 2498889
Apr 16, 2021 15:55:11.067 [0x7f387bc75780] DEBUG - Opening 2 database sessions to library (com.plexapp.plugins.library.blobs), SQLite 3.26.0, threadsafe=1
Apr 16, 2021 15:55:11.075 [0x7f387bc75780] DEBUG - Running migrations. (EPG 0)
Apr 16, 2021 15:55:11.100 [0x7f387bc75780] DEBUG - [CERT] Subject name is /C=US/ST=California/L=Los Gatos/O=Plex, Inc./CN=*.46ee67c328fc44ad819add2d41865999.plex.direct
Apr 16, 2021 15:55:11.101 [0x7f387bc75780] DEBUG - [CERT] Installed certificate with fingerprint b2:ac:1b:ea:d5:64:20:7e:5b:3f:59:bd:22:bf:9b:64:ee:1f:5c:31.
Apr 16, 2021 15:55:11.101 [0x7f387bc75780] DEBUG - [CERT/OCSP] Stapling requests will be made to 'http://ocspx.digicert.com/'.
Apr 16, 2021 15:55:11.101 [0x7f387bc75780] INFO - [CERT/OCSP] Successfully retrieved response from cache.
Apr 16, 2021 15:55:11.101 [0x7f387bc75780] DEBUG - HttpServer: Listening on IPv6 as well as IPv4.
Apr 16, 2021 15:55:11.101 [0x7f387bc75780] DEBUG - HttpServer: Listening on port 32400.
Apr 16, 2021 15:55:11.101 [0x7f387bc75780] DEBUG - HttpServer: Listening on port 32401.
Apr 16, 2021 15:55:11.117 [0x7f386b28d700] DEBUG - Grabber: Cleaning up orphaned grabs.
I see the server commanded (App Center) to stop
Apr 16, 2021 17:07:03.058 [0x7f386af9f700] DEBUG - Completed: [192.168.68.144:62778] 200 GET /clients (10 live) 0ms 623 bytes (pipelined: 1)
Apr 16, 2021 17:07:03.270 [0x7f3871eae700] DEBUG - Shutting down with signal 15 (Terminated)
Apr 16, 2021 17:07:03.270 [0x7f3871eae700] DEBUG - Ordered to stop server.
Apr 16, 2021 17:07:03.270 [0x7f387bc75780] DEBUG - Stopping server...
Apr 16, 2021 17:07:03.270 [0x7f387bc75780] DEBUG - HttpServer: Stopping server.
Apr 16, 2021 17:07:03.270 [0x7f383d11f700] DEBUG - TranscodeJobManager: [Running] onServerShutdown
Apr 16, 2021 17:07:03.270 [0x7f383d11f700] DEBUG - TranscodeJobManager: [Running] -> [Shutdown]
Apr 16, 2021 17:07:03.270 [0x7f383d11f700] DEBUG - MetadataItemClusterRequestHandler: a shutdown event has been received
Apr 16, 2021 17:07:03.270 [0x7f387bc75780] DEBUG - Server stopped.
Apr 16, 2021 17:07:03.270 [0x7f387bc75780] DEBUG - NetworkService: Stopping advertisement.
Apr 16, 2021 17:07:03.270 [0x7f387bc75780] DEBUG - Killing plug-ins.
Apr 16, 2021 17:07:03.303 [0x7f387bc75780] DEBUG - [com.plexapp.system] Killing.
Apr 16, 2021 17:07:03.309 [0x7f3871eae700] WARN - JobManager: Could not find job for handle 28664
Apr 16, 2021 17:07:03.310 [0x7f387bc75780] DEBUG - ChildProcessMonitor: Waiting for Plex DLNA Server to exit.
Apr 16, 2021 17:07:03.621 [0x7f3871eae700] DEBUG - Jobs: '/share/CACHEDEV1_DATA/.qpkg/PlexMediaServer/Plex DLNA Server' exit code for process 30677 is 0 (success)
Apr 16, 2021 17:07:03.621 [0x7f383d6fb700] DEBUG - [ChildProcessMonitor] Plex DLNA Server exited.
Apr 16, 2021 17:07:03.621 [0x7f387bc75780] DEBUG - ChildProcessMonitor: Waiting for Plex Tuner Service to exit.
Apr 16, 2021 17:07:03.621 [0x7f387bc75780] DEBUG - [JobRunner] Signalling job ID 30687 with 2
Apr 16, 2021 17:07:03.677 [0x7f3871eae700] DEBUG - Jobs: '/share/CACHEDEV1_DATA/.qpkg/PlexMediaServer/Plex Tuner Service' exit code for process 30687 is 0 (success)
Apr 16, 2021 17:07:03.677 [0x7f383d40d700] DEBUG - [ChildProcessMonitor] Plex Tuner Service exited.
Apr 16, 2021 17:07:03.689 [0x7f387bc75780] DEBUG - Database: Shutting down.
Apr 16, 2021 17:07:03.689 [0x7f387bc75780] DEBUG - Captured session 0.
Apr 16, 2021 17:07:03.689 [0x7f387bc75780] DEBUG - Captured session 1.
Apr 16, 2021 17:07:03.689 [0x7f387bc75780] DEBUG - Captured session 2.
Apr 16, 2021 17:07:03.689 [0x7f387bc75780] DEBUG - Captured session 3.
Apr 16, 2021 17:07:03.689 [0x7f387bc75780] DEBUG - Captured session 4.
Apr 16, 2021 17:07:03.689 [0x7f387bc75780] DEBUG - Captured session 5.
Apr 16, 2021 17:07:03.689 [0x7f387bc75780] DEBUG - Captured session 6.
Apr 16, 2021 17:07:03.689 [0x7f387bc75780] DEBUG - Captured session 7.
Apr 16, 2021 17:07:03.689 [0x7f387bc75780] DEBUG - Captured session 8.
Apr 16, 2021 17:07:03.689 [0x7f387bc75780] DEBUG - Captured session 9.
Apr 16, 2021 17:07:03.689 [0x7f387bc75780] DEBUG - Captured session 10.
Apr 16, 2021 17:07:03.689 [0x7f387bc75780] DEBUG - Captured session 11.
Apr 16, 2021 17:07:03.689 [0x7f387bc75780] DEBUG - Captured session 12.
Apr 16, 2021 17:07:03.689 [0x7f387bc75780] DEBUG - Captured session 13.
Apr 16, 2021 17:07:03.689 [0x7f387bc75780] DEBUG - Captured session 14.
Apr 16, 2021 17:07:03.689 [0x7f387bc75780] DEBUG - Captured session 15.
Apr 16, 2021 17:07:03.689 [0x7f387bc75780] DEBUG - Captured session 16.
Apr 16, 2021 17:07:03.689 [0x7f387bc75780] DEBUG - Captured session 17.
Apr 16, 2021 17:07:03.689 [0x7f387bc75780] DEBUG - Captured session 18.
Apr 16, 2021 17:07:03.689 [0x7f387bc75780] DEBUG - Captured session 19.
Apr 16, 2021 17:07:04.121 [0x7f387bc75780] DEBUG - Database: Shutting down.
Apr 16, 2021 17:07:04.121 [0x7f387bc75780] DEBUG - Captured session 0.
Apr 16, 2021 17:07:04.121 [0x7f387bc75780] DEBUG - Captured session 1.
In between, I see activity from a Windows client.
Is that what I should be seeing?