The major downside to the single file storage used by Keepass is that it's easy to accidentally create a conflict between files on different devices if they're not synced immediately. Conflicting files have to be merged manually or data might be lost. I've run into this several times with Keepass + Nextcloud. In comparison, a central master database with local cache can resolve conflicts between individual records.
Bollocks. I've seen that many times with Flatpak (can't speak for Snap), and every single time it was either because the packager failed to set up permissions or because the user messed with permissions that the application needed. Break off the tip of a screwdriver and it will no longer function as a screwdriver.
And I know you're talking out of your ass because AppImage isn't even sandboxed.
taking GBs of space
That part is true and accurate, and for a very good reason: dependency pinning. System packages can break if they don't have the correct versions of shared libraries. If a package requires a very old version of a library, and doesn't link it statically or supply it with the package, it can misbehave, have missing features, or refuse to even start. Flatpak (and probably Snap too, can't speak for it) solves that by letting the packager specify (pin) the exact version of a dependency. If five separate packages require five different versions of the GNOME application framework, then they will download five separate packages of the correct version. AppImage solves it by being monolithic: everything is packaged together into a single executable.
People for the last twelve thousand years: "Hunting and gathering cannot support the needs of a growing population. We should create a system where crops can be grown efficiently and in high quantities, and animals can be bred and raised. It will be labour-intensive and require specialized knowledge, skills, and equipment, it will lead to the economic stratification of society, but it's the best way to not have most of our people starve to death."
One guy who recently read the Communist Manifesto (abridged version): "But food is literally free!"
Regular or long-term use of over-the-counter painkillers will fuck up your liver and kidneys. Acetaminophen/paracetamol harms the liver, and ibuprofen and aspirin harm the kidneys.
(edit) What I mean to say is, if you need pain medication several times a week to get through the day, talk to a real physician because there are likely more serious underlying issues, and destroying your body for temporary relief will not solve them. Don't just pop the pill because an internet stranger says it's okay.
I don't know the exact situation with Rainbolt, but it's common for stream clip channels (even "official" ones) to be operated by people other than the streamer. Example.
Tailscale should work. It uses Wireguard and does some UDP fuckery to get around the firewall and NAT (including CGNAT). I can stream Jellyfin through it at 1080p native with no significant buffering, it'll work for music.
ZSH still needs the completion data files to be installed. It won't just magically know the completions.