There is a way without Google Play outlined here: https://support.symfonium.app/t/how-can-i-pay-for-symfonium-without-google-play/1290/2
I haven't used it myself, but I've heard of ErsatzTV. Their docs note configuring Jellyfin as client.https://ersatztv.org/docs/intro
I suggest Vikunja. There isn't a mobile app to my knowledge, but the web UI on mobile and desktop is very responsive. It should cover the rest of the items on your list
Would you mind sharing your hardware setup?