Resident Evil 1's remake and the OG Resident Evil 4 are still must-plays, and you can make them both look even better with HD remaster mods
The GameCube era of the early 2000s was a magical time for Resident Evil. Not only did Capcom return to the first game, releasing a much more challenging and intense remake (where mutating, self-reviving enemies first appeared, a feature every Requiem player is VERY familiar with by now), but it also pushed the genre towards a new, more action-oriented era with the gloriously camp Resident Evil 4.
Liberated from the GameCube and now over 20 years old each, both REmake and the OG RE4 are available with some mild enhancements on Steam.