Same problem for me, with a <8GB zip file I cannot upload due to insufficient resources.
I’m with 1.5.14 (after moving back from 1.5.16 due to Unable to create new Cryptomator vault on a network share mounted in Windows
On this I can add that, except for the first time, I’m not able to open the vault mapped virtual drive for the same reason. If I unlock and show it, it works. As soon as I close the windows (letting the vault open), I’m no more able to open the virtual drive due to “insufficient resources” (on a PC with 32GB RAM!).