Here is what I see in my win10 machine C:\Program Files\Graylog\sidecar\logs
folder on a clean initial start. You can stop the win10 service, clear the logfiles directory and start up again - perhaps compare with what I have here. The last line in winlogbeat is where it sent events into Graylog “successfully published 21 events” you should have all the log lines similarly to mine leading up to that the any thing missing is likely a clue as to something you are missing. If you are getting all the way to it publishing events (may take a minute) then it is somethign in Graylog that is not receiving correctly.
sidecar.log:
time="2021-06-22T10:06:14-04:00" level=info msg="Starting signal distributor"
time="2021-06-22T10:06:24-04:00" level=info msg="Adding process runner for: winlogbeat"
time="2021-06-22T10:06:24-04:00" level=info msg="[winlogbeat] Configuration change detected, rewriting configuration file."
time="2021-06-22T10:06:24-04:00" level=info msg="[winlogbeat] Starting (svc driver)"
winlgobeat.log
2021-06-22T10:06:24.519-0400 INFO instance/beat.go:660 Home path: [C:\Program Files\Graylog\sidecar] Config path: [C:\Program Files\Graylog\sidecar] Data path: [C:\Program Files\Graylog\sidecar\cache\winlogbeat\data] Logs path: [C:\Program Files\Graylog\sidecar\logs]
2021-06-22T10:06:24.521-0400 INFO instance/beat.go:668 Beat ID: ad8zzzfc-x0x0-42fd-8acc-4960c08abfc0
2021-06-22T10:06:24.521-0400 INFO [beat] instance/beat.go:996 Beat info {"system_info": {"beat": {"path": {"config": "C:\\Program Files\\Graylog\\sidecar", "data": "C:\\Program Files\\Graylog\\sidecar\\cache\\winlogbeat\\data", "home": "C:\\Program Files\\Graylog\\sidecar", "logs": "C:\\Program Files\\Graylog\\sidecar\\logs"}, "type": "winlogbeat", "uuid": "ad8ef7fc-x0x0-22ed-8acc-4960c08abfc0"}}}
2021-06-22T10:06:24.521-0400 INFO [beat] instance/beat.go:1005 Build info {"system_info": {"build": {"commit": "9b2fecb327a29fe8d0411114d8a2e42a3ftyyt4b", "libbeat": "7.11.1", "time": "2021-02-15T13:07:49.000Z", "version": "7.11.1"}}}
2021-06-22T10:06:24.521-0400 INFO [beat] instance/beat.go:1008 Go runtime info {"system_info": {"go": {"os":"windows","arch":"amd64","max_procs":8,"version":"go1.14.14"}}}
2021-06-22T10:06:24.527-0400 INFO [beat] instance/beat.go:1012 Host info {"system_info": {"host": {"architecture":"x86_64","boot_time":"2021-06-21T08:16:01.92-04:00","name":"MY-ADMIN-WORKSTATION","ip":["fe80::cda:a7b4:43e0:943f/64","10.33.33.33/16","192.168.71.55/24","::1/128","127.0.0.1/8"],"kernel_version":"10.0.19041.1052 (WinBuild.160101.0800)","mac":["00:ff:f4:35:65:22","34:17:eb:qw:15:87"],"os":{"family":"windows","platform":"windows","name":"Windows 10 Pro","version":"10.0","major":10,"minor":0,"patch":0,"build":"22.22"},"timezone":"EDT","timezone_offset_sec":-14400,"id":"5036eb30-cf6d-4581-867d-70401d478809"}}}
2021-06-22T10:06:24.527-0400 INFO [beat] instance/beat.go:1041 Process info {"system_info": {"process": {"cwd": "C:\\WINDOWS\\system32", "exe": "C:\\Program Files\\Graylog\\sidecar\\winlogbeat.exe", "name": "winlogbeat.exe", "pid": 12356, "ppid": 1000, "start_time": "2021-06-22T10:06:24.438-0400"}}}
2021-06-22T10:06:24.527-0400 INFO instance/beat.go:304 Setup Beat: winlogbeat; Version: 7.11.1
2021-06-22T10:06:24.527-0400 INFO [publisher] pipeline/module.go:113 Beat name: MY-ADMIN-WORKSTATION
2021-06-22T10:06:24.527-0400 INFO beater/winlogbeat.go:69 State will be read from and persisted to C:\Program Files\Graylog\sidecar\cache\winlogbeat\data\.winlogbeat.yml
2021-06-22T10:06:24.528-0400 INFO instance/beat.go:468 winlogbeat start running.
2021-06-22T10:06:24.528-0400 INFO [monitoring] log/log.go:117 Starting metrics logging every 30s
2021-06-22T10:06:25.549-0400 INFO [publisher_pipeline_output] pipeline/output.go:143 Connecting to backoff(async(tcp://MY-GRAYLOG-SERVER:5044))
2021-06-22T10:06:25.549-0400 INFO [publisher] pipeline/retry.go:219 retryer: send unwait signal to consumer
2021-06-22T10:06:25.549-0400 INFO [publisher] pipeline/retry.go:223 done
2021-06-22T10:06:25.556-0400 INFO [publisher_pipeline_output] pipeline/output.go:151 Connection to backoff(async(tcp://MY-GRAYLOG-SERVER:5044)) established
2021-06-22T10:06:25.559-0400 INFO beater/eventlogger.go:88 EventLog[Security] successfully published 21 events
...
winlogbeat.1
2021-06-22T10:06:24.418-0400 INFO instance/beat.go:660 Home path: [C:\Program Files\Graylog\sidecar] Config path: [C:\Program Files\Graylog\sidecar] Data path: [C:\Program Files\Graylog\sidecar\cache\winlogbeat\data] Logs path: [C:\Program Files\Graylog\sidecar\logs]
2021-06-22T10:06:24.419-0400 INFO instance/beat.go:668 Beat ID: ad8ef7fc-0a4d-42fd-8acc-4960c08abfc0
2021-06-22T10:06:24.419-0400 INFO [beat] instance/beat.go:996 Beat info {"system_info": {"beat": {"path": {"config": "C:\\Program Files\\Graylog\\sidecar", "data": "C:\\Program Files\\Graylog\\sidecar\\cache\\winlogbeat\\data", "home": "C:\\Program Files\\Graylog\\sidecar", "logs": "C:\\Program Files\\Graylog\\sidecar\\logs"}, "type": "winlogbeat", "uuid": "ad8ef7fc-0a4d-42fd-8acc-4960c08abfc0"}}}
2021-06-22T10:06:24.419-0400 INFO [beat] instance/beat.go:1005 Build info {"system_info": {"build": {"commit": "9b2fecb327a29fe8d0477074d8a2e42a3fabbc4b", "libbeat": "7.11.1", "time": "2021-02-15T13:07:49.000Z", "version": "7.11.1"}}}
2021-06-22T10:06:24.419-0400 INFO [beat] instance/beat.go:1008 Go runtime info {"system_info": {"go": {"os":"windows","arch":"amd64","max_procs":8,"version":"go1.14.14"}}}
2021-06-22T10:06:24.424-0400 INFO [beat] instance/beat.go:1012 Host info {"system_info": {"host": {"architecture":"x86_64","boot_time":"2021-06-21T08:16:01.91-04:00","name":"MY-ADMIN-WORKSTATION","ip":["fe80::cda:a7b4:43e0:943f/64","169.254.148.63/16","192.168.2.182/23","::1/128","127.0.0.1/8"],"kernel_version":"10.0.19041.1052 (WinBuild.160101.0800)","mac":["00:ff:f1:35:65:63","34:17:eb:cd:15:87"],"os":{"family":"windows","platform":"windows","name":"Windows 10 Pro","version":"10.0","major":10,"minor":0,"patch":0,"build":"19043.1052"},"timezone":"EDT","timezone_offset_sec":-14400,"id":"5036eb30-cf6d-4581-867d-70401d478809"}}}
2021-06-22T10:06:24.424-0400 INFO [beat] instance/beat.go:1041 Process info {"system_info": {"process": {"cwd": "C:\\WINDOWS\\system32", "exe": "C:\\Program Files\\Graylog\\sidecar\\winlogbeat.exe", "name": "winlogbeat.exe", "pid": 8396, "ppid": 7296, "start_time": "2021-06-22T10:06:24.216-0400"}}}
2021-06-22T10:06:24.424-0400 INFO instance/beat.go:304 Setup Beat: winlogbeat; Version: 7.11.1
2021-06-22T10:06:24.425-0400 INFO [publisher] pipeline/module.go:113 Beat name: MY-ADMIN-WORKSTATION
2021-06-22T10:06:24.425-0400 INFO beater/winlogbeat.go:69 State will be read from and persisted to C:\Program Files\Graylog\sidecar\cache\winlogbeat\data\.winlogbeat.yml