I thought about it with the 24-70 F4 and the FZT adapter, but it's still around 2200€ without an XQD card, which is additional ~100€ for 32GB.
As long as my old D7100 is still working, I think I will keep it. Or maybe the prices will be very attractive in 2 years, or maybe they will release an APS-C DSLM.