MOS cut could have been deeper, but screws have adequate (no more, no less) thread engagement, these are not the problem. Attempts to treat the symptoms by using stronger screws haven't fared well, because they don't fix the real issue, which is the sight moving on the plate in recoil.
OPF-G, RMR uses the same spec screws, but OPF-G, RMR design holds the sight immobile between the two recoil lugs and the plate's front recoil fence/lug, the screws have but only one job to do, that is to hold the sight down, they're no longer subject to the beating sustained on OEM plates. If the sight is allowed to reciprocate in recoil, sight to plate screws handle load and get beat up on, they're not designed to handle either, this no screws strong enough, or long enough can fix.
Same screws, different plate designs, while OEM plate loosens and shears screws, ours doesn't. The sight to plate screws are not part of the solution. Fix the sight moving on the plate in recoil, you fix everything else.