Try the Oracle Cloud free tier. It’s the best price you can get for a very beefy server: 4 arm64 cores with 24 GB RAM and 250 GB storage. Just don’t put too personal data on there.

For the notifications I would use https://ntfy.sh/ but that doesn’t give you the return channel.

Unstable always. Very rarely the build breaks, but that just means I can’t update my systems for a few days. Due to the atomic updates, my systems themselves have never broken.