Pair Droidify with Shizuku (also on IzzyOnDroid) and you’ve got automatic updates.

https://apt.izzysoft.de/fdroid/index/apk/moe.shizuku.privileged.api

This is subjective, but after distro hopping, Linux Mint XFCE requires the least amount of post install configuration for my use case and personal preferences.

Also, they show a preference for flatpack over snap but don’t lock you in/out of either.

OpenKeychain is great for keys on Android. It’s FOSS and available on FDroid. +1 for using a self hosted Nextcloud instance to keep things in sync.