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.
The only one I saw I kind of liked was the Titan, but it seemed a bit out of date (not sure if it gets updates, and I didn’t see it listed as supported for LineageOS).
Yeah, these use MediaTek SOCs, and required source code is not available. Which is why the custom ROM scene is so lacking on MediaTek side. And I wouldn’t expect updates from brands like this, unfortunately.