yeah, RE4 is absolutely in the conversation if we widen the scope of the question. although I think gears might still be the most influential even including RE4, just because a lot of games attempted to iterate on RE4 but the gears iteration is the one that really stuck with mainstream design. RE4 is the progenitor without which we wouldn't have gears, but throughout all the PS360 generation and beyond I think studios were looking at gears more directly if that makes sense.
Yeah. I think the Gears influence is more easy to immediately see in mechanics. Even in the worst of it, like the amount of games that suffered from "Press A to do everything". TPS as a whole seemed to lean more into having cover be a natural part of it, possibly since it's more unique to the perspective and not something an FPS can easily replicate.
RE4 seems more on the abstract things like pacing or encounter design, but is mostly directly in atmosphere. Though I would ask more games to take the Tetris inventory directly because that shit's cool.