Perhaps overkill for your use case, but uv is pretty great. I suppose you could just use it to install a local python and then add it to your path.

deleted by creator

Are you actually trying to send mail from your own smtp server? You mention apache and pihole which are completely unrelated.

Check the error. You want www.hexbear.net instead

Guessing you’re not ipv6 only, but strace could still be of help: https://www.raspberrypi.com/news/host-your-own-mastodon-instance-on-a-raspberry-pi/