I placed an order but the max ram writen on the website seems to indicate 64GB max. But out of curiosity, is it possible to upgrade to 2x48GB or 2x64GB DDR5-5600 on the framework 16? Will it be support by the motherboard?

As as far as I check the Ryzen 9 7940hs does support up to 256GB of ram.

Crucial currently has the 48Gb dimm available.