The second one is harmless (appears on all hardware running LE) and can be ignored.
The first one is related to UPnP support .. no idea what the issue is though. In general your logs are so full of deprecated warning garbage that its hard to see what's really going on.
Any pointers or advice would be appreciated, thank you.
Report add-on issues to the add-on maintainer via the add-on support thread in the Kodi forums .. it's not an LE issue.
Initiative test .. what happens when you type "LibreELEC debug log" into Google?
Enable debug loging .. clean boot .. demonstrate the problem .. run "pastekodi" and share the URL generated. From this we can see properties of the media being played and resolution changes etc.
Pithy comments normally inspire the forum staff to ignore posts. Just saying..
In the absence of a boot log .. 
I have never seen anyone using Radarr/Sonarr outside of a Torrenting setup; which means piracy; which means I didn't read the original post beyond those words. And just because I have a high post count doesn't mean you can assume personal support.
Apr 23 15:12:13.064341 LEMC kernel: EXT4-fs (sdb1): error count since last fsck: 13
Apr 23 15:12:13.064824 LEMC kernel: EXT4-fs (sdb1): initial error at time 1598463659: ext4_validate_block_bitmap:384
Apr 23 15:12:13.065026 LEMC kernel: EXT4-fs (sdb1): last error at time 1599941347: ext4_free_blocks:4964Both drives were fsck'd on boot due to dirty filesystems (not unmounted cleanly before shutdown) but it's impossible to see/say what causes the shutdowns. The ^ above errors suggest the drive has errors after being fsck'd so it might be dying. The largest cause of drive mounting issues and instability on RPi boards is an inadequate power supply. And power characteristics of the board under LE11 may also be different than LE9 due to major software changes and general evolution. If you're adding drives then the board is going to draw more current even if the drives are powered from a separate hub or via their own PSUs.
Amlogic S905X4 devices are not currently supported, and no timeline to support.
Banned add-ons are installed. No support will be provided.
Please report the issue to the YouTube add-on authors via the Kodi forum add-on support thread (when the Kodi forum is online again). It is not a LibreELEC issue.
The LE11 Generic image now uses GBM/V4L2 graphics so there are differences to LE10. If you switch to the Generic-Legacy image it should replicate the LE10 experience, but no support for HDR (same as LE10).
The newer graphics pipeline doesn't support multiple outputs so the future update (when the Legacy image is dropped) would be to use an HDMI audio splitter on the (single) connection to the TV and feed the AVR that way (cheaper than replacing the AVR).
I'm aware of that effort and have spoken with the authors. To simplify the codebase needed for it to work on RK hardware they removed all the Amlogic support code so it remains a dead-end. And even on RK hardware the results aren't great (so they've said).
So what I would like to know now: Does shutdown work with LE 10?
There are no released LE10 images, so nobody knows.
It's not a debug log .. and you don't demonstrate the problem by playing anything. So not much use for investigations.
Unrelated to the problem, I do see that the Hyperion add-on is continuously faulting in the background. It's not supported under LE10/LE11 so you might as well disable / remove it.
Clean boot with debug logging enabled .. demonstrate the problem .. run "pastekodi" and share the URL so we can look for things.
Kodi feature requests should be made to the Kodi developers via the Kodi forums (when back online).
