Thanks for the hint, which forced me to get rid of berryboot and try something different, which in the end led to a solution.
I was sure we added a middle-finger icon to the smilies to deal with BerryBoot Q's .. but we appear to have gone polite-mode in the forum at some point. I'll just have to feign surprise instead 
AMD support has always been (and continues to be) a little bit of a lottery. It might be worth experimenting with LE11 nightlies; newer kernel and drivers and we also switch from Xorg to native GBM/KMS.
Most of the PVR add-ons in the LE repo are client add-ons, so you will need to have the corresponding DVB server application installed and running somewhere in the network for the client to connect to.
Otherwise the mention of installng a repo and add-ons (with no names) and then PVR sounds a like a user trying to setup IPTV simple with a bunch of pirate feeds. If that's the objective you aren't going to get much help around here. If not the case, you need to explain what you are trying to do in more detail and provide log files to demonstrate/show what the issue is - because it's not clear from your description.
ConnMan stores service profiles in /storage/.cache/connman/<servicename>/settings but the file is owned by ConnMan so it will ignore all changes made while ConnMan is running and may overwrite them at any time. So edits require you to either make changes through the connmanctl app, or you need to "stop > edit > restart" the service to make changes.
You can also try an LE11 nightly (back-up the current /storage/.kodi dir first so you can revert easily) as the nightly image has newer connman and also switched to iwd instead of wpa_supplicant.
LE 9.2 is optimised towards RPi0/1/2/3 hardware (RPi4 is not feature complete) and LE 10+ is optimised towards RPi4 (and RPi 0/1/2/3 are not as featured) using an entirely new/different video pipeline. RPi devs will continue to improve things but I wouldn't expect massive changes in the future. The older RPi display codebase contains quite a few clever hacks that aren't upstreamable and thus deliberately won't be repeated in the newer codebase.
There shouldn't be anything different between RPi and Amlogic in terms of USB audio support.
Try removing the 4096 modes from the whitelist, leaving only the 3840 "4K" modes. Any better?
The rainbow screen normally indicates missing, obsolete or wrong boot files. RPi4 has gone through several hardware iterations since launch and the LE 9.2.8 image? is now quite old and has boot firmware that does not support the latest iterations of RPi4 hardware. The LE 10.0.3 image is superior in just about all aspects on RPi4 hardware so please try that.
You can install the Multimedia Tools add-on from the LE repo using the GUI. There is no simple way to install add-ons from the command line and there is no package management in the OS.
I'm wondering if the SD card is being reset correctly in reboot. Have you tried installing the image to emmc storage? (which removes SD card from the process). I forget when I last booted this board, but it was probably booted from emmc.
No kodi debug log = No problem for us to investigate. If it's a pirate IPTV source you can skip the process because we won't support it.
You can partially restore some the content of the backup (add-on settings, databases and thumbnails, etc.). Just avoid add-on binaries as those will be for 'arm' CPU architecture and will not run on x86_64 hardware.
There is no support for piracy infested forks in this forum and you aren't using LE on any devices. So i'll point out that a lighthttpd package is already in the buildsystem as a Kodi dependency, but beyond that you're on your own.
Run "journalctl | paste" and share the URL from a cold/clean boot and after a minute or so.
The USB audio card route would be best, as this provides an independent soundcard to route audio to. I'm not sure if the current behaviour is hardwired in hardware (in the SoC) or in the kernel, but I suspect the former if both legacy and modern kernel images behave the same, as those kernel codebases have almost zero driver code in common.
The samba server is configured to require credentials. The default user = libreelec, and pass = libreelec .. unless you change them in the LE settingsd add-on. So enter the details and store the credential in the local keychain and the GUI shouldn't prompt you again. Or change the user to match whatever credential you have previously stored for the same host (looks like user = kodi, pass = ???).
Anyone running that piracy infested garbage is on their own. Good luck.
I trashed the log post, because a) the URL was invalid, b) when you fix it, it links to a garbage post on crypto crap
