Double sided perfboards way more often than not don’t have plated vias. The vast majority are just etched from a 2 layer blank without any post processing.

You would have to solder specifically on both sides in order to increase the strength.

But yes pads lifting is almost exclusively from dumping way too much heat in it. Because there is no plated through hole, it also has ~1/4 of the thermal mass so it is easier to overheat and damage the adhesive.