Short answer (as far as I am concerned): No.
2 - I have to keep re-synching the TV audio
What exactly do you mean by re-synching? Changing the HDMI delay to get sound and picture. n synch? In your TV's settings? Does it have an auto-synch setting?
Looks to me like this might be a problem with what's coming into the WiiM Ultra. Make sure you have eARC disabled on your TV (however it might be called with your brand). WiiM only supports ARC, not eARC. Watch the quality of the HDMi cable. The one supplied with the Ultra seems to work very well (with very few exceptions reported here). Even though ARC has been introduced with HDMI 1.4 I'd always go with a version 2.0.or newer cable (a certified one) if you buy it on your own.
Remove the mains power from all devices before making any HDMI connections. Occasionally issues could be fixed by just powering down (really pull the plugs!) all connected devices, let it sit for a minute, undo and redo the HDMI connection and power up everything again. Yes, sounds spooky.
3 - When using the WiiM remote to cycle through inputs, occasionally the volume completely cuts out and I have to reboot the Ultra to get it working again.
When this happens,.did you check with the WiiM Home app if the input has really been changed as you expect it to? Or even easier: What's shown on the touchscreen? Some inputs may take longer to switch too. If an input gets muted you should see the play symbol on the touchscreen for a short time,.so make sure that flipping through the sources just not mutes the unit.
Unfortunately there is no feature yet to skip unused inputs.
If nothing of this is of any help (or nobody comes up with better ideas), make sure to send feedback to WiiM from within the WiiM Home app on your phone right after the problem occurs. WiiM Home app >> More >> Send us feedback. This will send device logs along with your description.