>> I am advocating a GIL per-thread model with an explicit feature for sharing selected objects

> Is there a PEP or something written about it? I don't like this idea at first glance. Feels like another hack. Though I have to admit it sounds better than the annoying multiprocessing approach.

This seems very similar to Perl's ithreads model: https://perldoc.perl.org/perlthrtut#Shared-And-Unshared-Data