Thanks. I figured out, that it can record play back from BIAB, if I change audio driver to MME and set audio input in bandicam to Win10 Sound.

But I'm stranded, because I can not record the sound of my guitar, only the BIAB play back.

I can record guitar in a BIAB track, even though I don't hear while recording the audio track. This is maybe a reason why I cannot record my guitar in bandicam. There are many RME sources I can choose in sound input, but nothing happens. Guess it's not possible with RME.