I think 90% chance of apple going for the EU-Specific model just like they did for Digital markets act, 10 chance of screws, 0% chance of actually popping the back cover off with bare hands.
For Samsung, 50% chance EU-Specific models 40% chance screws, 10% chance back cover tool-less removal. (Edit: typo)
As for other smaller manufacturers, probably just 50%/50% either screws or tool-less back cover removal.
Not to invalidate your experience but I have never seen one with screws yet I have never heard of a back cover accidentally popping off (aside from extreme falls). My current one isn’t removable but each one before this was, and I would for years fidget with it by popping the cover on and off, and even after that it held on just fine. Though screws would regardless be more secure and that is good, I agree.
I still have a Samsung Galaxy S2, which has such a cover. From the beginning, the phone would lose its back cover (and the battery would fall out) whenever it hit the ground, even just from a table. I solved it with getting a thin plastic phone case, and even after 14 years the phone works just fine.
We would visit family abroad multiple times a year, and so we had SIM cards for both countries. This meant popping the phone open at least 6 times a year, so it got worn down plenty. It happened very frequently that my phone spilled open when dropped, but I’m happy for you that you didn’t have the same result!