You cannot move progression between different store versions on PC (e.g., Epic Games to Steam) by swapping files.
There is a philosophical divide in the Hitman community. Hitman 3 100 Save File Steam
Use a 100% save file for a second playthrough or a sandbox experience, but avoid it if you are a completionist chasing Steam achievements legitimately. You cannot move progression between different store versions
The community's "deep" interest in these files generally falls into three philosophical buckets: Preservation and Liberation Hitman 3 100 Save File Steam