Hey there, have you checked your redis server version?
We had problems that we gut duplicated downlink frame-counter on our devices and no response packets were visible in the web-ui - upgrading redis to a version of 7.4.1 (ubuntu server) solved our issue.
See also our initial report: Downlink Frame Counter (application) not increasing · Issue #605 · chirpstack/chirpstack · GitHub
And the issue that brought us to our solution: Issue with Duplicate Packets on Different Frequencies After Upgrading to v4.11.0 - #6 by landinger