Hello everyone,
First of all, thanks for the helpful comments. I have just ordered a Lexon crank, 29mm DUB and 170mm.
Along with a Power2max (P2M) it fits really good. My frame has a BSA bottom bracket and I have a Moquai BB with ceramic bearings. A 3mm spacer on the drive side (recommended in the BB manual) and the crank fits perfectly. Chainline and shifting performance seems good, but so far only tested on the indoor trainer.
Tip: I bought the crank from the Lexon Ebay store and not from Aliexpress. It was a much cheaper alternative, at least for shipping to Germany - maybe do a cross check to save a bit.