If i plug the pi into the receiver, I get 7.1 sound but no 4k. If I plug it into the TV, I get 4k but no 7.1.
It proofs that LE provides A/V fine. You can try 7.1 output channels on LE's audio settings. Maybe your TV does proper pass-through with that. Another approach is to use both HDMI ports of the RPi 4: HDMI-0 for video, HDMI-1 for audio.
Isn't it dtoverlay=justboom-digi?
The receiver amp cant handle anything "HD" so DTS-HD is no loss.
Then you pass-through HD audio to a device that can't handle it. Please disable pass-through on LE audio settings now.
Maybe the HAT can't handle such high data rate. Anyway, please post the result of the test. 
When using "OK" -> "Pause" via CEC RC, I get the same GUI overlay on LE 9.2.8 and LE 11 nightly. So we eventually talk about different ways to pause a video.
Probably that HAT can deal with DTS / Dolby Digital, but I'm skeptical about any HD audio format (you had DTS-HD in the log).
Chances are you did the upgrade wrongly. When switching from LE 9.2.x to LE 10+, always do a fresh install on microSD.
The log looks fine to me now. If you need support for the Netflix add-on, then better ask at the Kodi forum, because most add-on developers are there.
Problem solved?
OK, so I had deeper a look at post #1. I also think the error is related to an add-on, and the hardware is fine.
From what I see at the log, the Google cloud add-on could be the culprit. I'm not familiar with Google cloud - maybe it's just a setup thing.
Generally you should find the faulty add-on by trial-and-error. Uninstall add-ons step-by-step until you get a working system.
PS: 45$ for an HP T430 is a steal by the way. In Germany I have to spend 199€ at least.
I think at this point I have thrown away $90 lol.
Two HP T430? Not very likely that both devices have broken hardware. Activate debug logging at GUI (HUD will appear), reboot, run pastekodi and post the resulting link.
Also have a look at the EFI / BIOS setup. Maybe this setup is the culprit.
Please uninstall or de-activate the Netflix add-on, reboot and try again. This add-on seems to produce errors in the background.
If slowness persists, activate debug logging at GUI (you are currently at log level 0). This will make a HUD overlay appear on top of the screen. Then reboot, login by SSH, run pastekodi and post the resulting link.
Please select the S/PDIF variant of your USB audio interface (card 2 / device 2) on output device settings. Maybe an LE update did the switch to card 2 / device 1.
After dev talk I can say that the audio pass-through is independent of the target device. All available audio channels go out, including LFE.
The HDMI-1 port should send audio without any settings (user reports somewhere on this forum). Because the splitter is very likely the culprit, you don't need HDMI-1. Just replace the splitter.
OK, I don't know Rufus. If it's a bad SD card, then Etcher will detect that, because it does verification after writing.
kenmills Same result with Etcher?
There are "HDMI dummy plugs" available. They can emulate the existence of a TV with many A/V capabilities. So maybe this works:
It assumes that your current splitter is able to deal with all audio channels. If the splitter is the culprit, this approach can't work.
