On mobile I indeed also had that issue once. However I made sure they can't lock me out completely. The db is stored using the opensource sqlcipher, so one can open it and extract everything manually, if absolutely necessary. As long as they don't change this, I am fine. In the worst case that would still be a lot of effort for me, but not impossible.
The export has also improved a lot. You can now also export to JSON which includes all the data one could need.
I was in the same boat and therefore my nextcloud instance was mostly running for backwards compatibility with a few setups I have, while I mostly use seafile, immich and sogo. But a few days ago I updated to nextcloud hub 10 (I think that's with nextcloud 31 under the hood) and damn does that run smooth. I was so impressed I got motivated to finally setup the high performance backend for nc talk.
I still dislike PHP, but nextcloud just won back my heart a little.