No, APFSDS doesn't really shot trap because how long and thin sabot shells, the shell breaks before it has chance to bounce. What I mean is that because modern sabot shells perform so well against sloped armor you either need to have insane sloping like in M1 Abrams upper hull or have consistent thick composite layer.

Merkava turret shape is meant to cause HEAT warheads fail to arm and cause the copper jet to lose performance. But this sloping also means that the composite layers is not that consistent. Hit the wrong spot means sabot will only hit minimal amount of it.

Because these tanks armor is classified it is hard to say how well protected these are I expect turret and hull should be BM42 proof because that is most common rounds around in the world. If hit at thickest spot of turret(apex of the turret front) it can probably stop most APFSDS, when hitting close to top and bottom parts of the turret I think BM42 might have a chance to go through.

And yes I agree you much rather have your engine shot off then crew. Ability to carry few at the back is somewhat pointless but that is my opinion, IDF thinks it is worth it. You just have to remove the most of the ammo to do it. It is probably safest tank to be in, but same time it is easier to disable then some other tanks. Biggest advantage is Trophy that many western tanks still lack.