2x Kingston FURY Impact DDR5 16 GB, 5600 MHz, CL40 (KF556S40IB-16, CL40-40-40 1.1V)
Bought last week, installed today, did not go well at first. Only booted after a few tries, with a single stick in the right slot. After that I re-tested the left slot, and both at once, and it keeps booting fine. I guess the memory controller just needed an easier homework to train on first. 
(Also, isn’t this essentially the same poll as the following? I did not post there, since the RAM I was planning to buy was already mentioned by someone else and I did not want to post duplicates… [DDR5 ONLY] RAM Survey - Framework Laptop 13 (AMD Ryzen 7040 Series) and Framework Laptop 16 DIY )