While some regions allow users to create their own digital backups from their own physical cartridges for personal use, this does not extend to downloading those same files from the internet.
If you are looking for a ROM to improve performance via PC emulation, it is worth noting how the Switch version stacks up against other hardware. The Switch version of Sonic Frontiers is designed for portability but makes significant visual sacrifices: Am i safe if i download roms off the internet? sonic frontiers switch rom download
