When I buy frozen meat (maybe once every couple months) I unpackage, then repackage them into unfreezable portions with small plastic lunch bags/saran.
If someone has a better way please let me know. I don’t have infinite tupperware drawer space though.
Slipknots are ok but I think you may as well do a mean twist and tuck unless the bread is travelling. The knot can go bad* if you share bread with others.