This. Also, most AppImages are x86_64 only. If they don't explicitly say it's for aarch64/arm64 you are going to also need some fun architecture translation (box64, fex, ...) to make the thing run. At that point, it's in many cases easier to try building from source IMHO.
PS: Good luck on Wayland can also be added, given probonopd's (AppImage inventor) stance on Wayland. I'd advise to not waste time with AppImages on #MobileLinux.
+1 for Gapless. My library is not nearly as large, but it's still plenty quick (no noticeable delay) with my 1 digit gigabytes library and IMHO the best native feeling media player on Phosh/GNOME Mobile.
It also does the Album -> Artist -> Song thing (which made me notice that I still have not fixed every error in metadata I managed to add to a part of my Library by blindly applying musicbraiz suggestions via Tagger, but that's just a me thing).
It's pretty much "real". You can install every package in the repos via apt, and they should work. Caveats can apply with regards to stuff that needs extra adjustment for accelerated graphics or new kernel features.
It's not a font ... and it says LINMOB (for LINux on MOBile).
I drew it in GIMP ages ago (15 years maybe?); and did not have the time to come up with a new logo since. (I am not super happy with it myself - but it's not a priority, there's way more important stuff I don't have time for).
That said: Contributions welcome! (at https://framagit.org/linmob/linmob.frama.io)
This is great, even if at least one app in that collection is only available for x86_64, which makes it hard to actually run on a phone ;-) They also updated the Device Support section of metainfo guidelines: https://docs.flathub.org/docs/for-app-authors/metainfo-guidelines/#device-support . Looks like some apps on the KDE side still need proper metainfo to show up: https://invent.kde.org/teams/flathub/issues/-/issues/34
Modern Android? More like Modern GNOME - it's called adwaitapod and adwaita is the name of GNOME's style. :-)
No, it's just that when you use a mainline kernel, you're just not reusing all the Android (often user-space) drivers that make cameras work on Android and due to that stuff, starting from drivers for the SoC camera interface to the camera sensor have to be re-implemented. Whether you are on glibc (e.g., on Debian/Mobian) or musl/Alpine does not really matter.
Also, Camera APIs and the whole "desktop Linux" camera stack (think of things like debayering, white-balance) is nowhere near as developed as what Android has (and that, IUC, Ubuntu Touch can reuse on Halium by plumbing things together).
A Pixel 3a may be a good choice. It's older, but not huge—and it's very well-supported in Ubuntu Touch (and Droidian, both use Halium/libhybris to re-use the Android kernel drivers), and also in postmarketOS (mainline Linux 6.9.3 as of this message).
On postmarketOS, camera support is not fully there—the front camera is somewhat supported. Also, Wi-Fi is still a bit annoying, calls only work with headset on postmarketOS, so I would say: Use Ubuntu Touch or Droidian for now, and maybe move on to postmarketOS once it's a bit more solid.
It should be. With zram, I can use similar software even on a 2 GB RAM device somewhat comfortably, unless I open too many tabs in Firefox.
I recommend trying to use KDE Connect (or scp, rsync ... another network based way) to send the screenshot from the phone to your other computer instead.
MTP/other file transfer protocols do not (yet?) work with mobile Linux, so this failure is to be expected. It only shows up for connection, because if your device ran Android, it would be an option — AFAIK, Plasma acts this way because of the USB ID of the device.
Also, regarding your main issue: While you can report this to Mozilla, please be aware that Firefox is being "patched" to better work on mobile by https://gitlab.com/postmarketOS/mobile-config-firefox. I suggest you to install the latest, not yet in postmarketOS 23.12 mobile-config-firefox package from edge first by running:
sudo apk del mobile-config-firefox
sudo apk add mobile-config-firefox --repository http://mirror.postmarketos.org/postmarketos/master
While it may not fix every issue possible, it should improve the experience.
I've been told that PinePhone 2 is not happening this year. (If AllWinner will continue to supply A64 SoCs, it might take even longer.)
Regarding SoC, the likely/obvious candidate is RK3566 - but we'll have to wait and see for the when and how. (I, personally, would love to see a PinePhone V - think PineTab V, but as a phone).
PineTime: It has nice companion apps on Mobile Linux, but I went back to my Pebble Time Steel - the always on display matters to me.
Maybe https://wiki.postmarketos.org/wiki/Hybris can be helpful :-)