Start with running something in docker. Probably get containous/whoami running, then portainer, then either traefik or caddy.
Once you've got that all working, you can run anything you want easily.
If you've got an old machine lying around, you can use that to start.
I use a simplelogin domain when my custom one isn't accepted. (Everything goes through SimpleLogin anyway.)
You don't need a special client, just a browser. Otherwise, yep!
If you're carrying your media with you, you could run Jellyfin on the server to provide access to the media to anyone connected to its wifi.
We have a cat that does that too. She'll drink normally as well, though. I view it as her cleaning her little feet.
(I don't know what the problem with a water bowl is, but I digress)
(cats are more likely to drink moving water than still water since moving water is less likely to have bad things growing in it)
The machines haven't worked for me, so I just started opting out immediately as well, since that ends up being much faster. I don't understand the point of this.
Check out MXRoute. (Specifically the lifetime promo, though I've seen it on sale for cheaper.)
Take a look at Rhasspy.*
*Will take a lengthy setup. Maybe look at S.E.P.I.A.?
Check out Discord's Webhooks; many applications publish notifications through them. Should be as easy as sending a message to a specific URL, I think.
(disclaimer: I don't support the political views of ACLU)
The.. political views? As in, where they decided to stop defending Nazis?
No docker? :(