

Yep Probably you need to change ownership and/or permissions of the files outside of docker.
I dont want to give the wrong suggestion from memory so hopefully thats enough info to get you going in the direction of a fix. Basically see what user id owns the files inside of docker, make it the same uid outside of docker in the folder you are bind mounting.
The problem is that while docker is running as root (0) the searxng process internally runs as a user searxng with id 977
So your filesystem outside of docker needs to have those files assigned the right ownership.
This thread has a more detailed discussion that you might find helpful. https://forums.truenas.com/t/how-to-install-searxng-app-docker-permissions-issue/14049/10