There are a lot of really great free sound effects packs both on itch and elsewhere! A lot of them just require attribution, but it's something to consider for sure as a money saving option
Yeah, I found some really good stuff on https://sonniss.com/gameaudiogdc that are both royalty free and commercial quality. I can reveal now that I'm already working on the game having sounds. It's pretty amazing how different it feels when there are footstep sounds when moving :).