On my Gl2400’s and an older GL2200 the inputs all have just one screw and I have never had a problem with them.
As for your tight fitting XLR’s, are they a good quality connector like a Neutrik or Switchcraft? I have seen many times where lets just say with “lesser quality” connectors not fitting, not locking and or getting stuck in a mating XLR connector that is of good quality. The Qu’s all have real Neutrik connectors.