Yes. PS5 runs the PS4 version of RE6 without issues. Save Wizard also works for PS4 saves used on PS5.
A "modded save" is a game save file that has been altered outside of normal gameplay. On the PlayStation 4, standard save files are encrypted and tied to your specific PSN account. A "modded" save typically involves using third-party software (like Save Wizard or advanced hex editors) to change values such as: resident evil 6 modded save ps4 repack