frenchtoucan

Yes. I always disable it because I don't drive (typically).

Mailbox.org. You can connect via CalDav to your calendar there.

The Play Protect warning typically has an option to install anyway. Take another look.

LibreTube here too. I have multiple devices so the subscription sync with a Piped account is nice (so nice that it is the reason I use it over Newpipe).

I just checked and yes. When you use the link, it puts you in like a guest account to view the calendar.

It does, yes. I use the tasks.org app to manage.