Keep in mind that the DAC on the Pi is pretty awful so it might not sound great.

You might want to get a audio HAT or USB DAC.

I’ve been using NetNewsWire. It’a free and open source and works with FreshRSS.

https://apps.apple.com/gb/app/netnewswire-rss-reader/id1480640210

Yes it does. Only the MAC address you assigned to that IP will get it.

I’m pretty sure 2FA can work offline as well. You definitely don’t need an internet connection to perform 2FA with OTP codes.

This depends if you have a website on your domain and it appears on search engines. I do and had to modify Rspamd as bots were spamming addresses like abuse@ and other dictionary words.

PC with opnsense.