I have been troubleshooting an issue, and ultimately found the problem to be an older version of Redis.
I originally followed the getting started guide for Debian/Ubuntu here:
https://www.chirpstack.io/docs/getting-started/debian-ubuntu.html
Eventually, through troubleshooting and reviewing various posts here, I found the default Redis version for Ubuntu 22.04 LTS is too old. So, when the instructions above are followed, ChirpStack appears to work, but quietly has errors that cause issues (for me, the issues were with JoinAccept messages).
Please, consider following the Redis Install guide for APT in Linux:
Following the Redis install guide resolved the GETDEL errors for me.