kernel panic when running backup on Big Sur 11.3.1

It might be one of these:

com.ShapeServices.driver.HSAudioDevice

com.intel.driver.EnergyDriver

com.shape.cmio.driver.Mobiola

zoom.us.ZoomAudioDevice

Uninstall them one at a time, see what happens. Or, you can uninstall them all and reinstall one at a time to see which causes the panics.

If the panics cease with them all uninstalled, then it is likely a hardware problem.

The quickest way, is to run with nothing but power connected the System diagnostics:

https://support.apple.com/en-us/HT202731

Isn't there a possibility to analyse the kernel panic report in such a way to conclude whether it was one of the kernel extensions or the hardware?

No.

You could boot into Safe Mode. Safe Mode disables third party kernel extensions. However, if it does't happen a lot, Safe Mode may be difficult to put up with waiting to see if a panic occurs.

Apple Diagnostics only looks at major components, not things associated with a kernel panic. Bad RAM is about all it can detect. It won’t find bad logic boards or small flaws in the GPU.

However, you do have four kernel extensions loaded which I have never heard of. Odds are quite high it is at least one of them. Almost nobody is capable of writing one that doesn’t cause panics.

I wasn’t aware zoom used a kext. Another good reason to avoid Zoom.