Are Roms (especially Nintendo games) legal?

I read that Rome downloads should be illegal, I mean especially N64 and Gameboy Advance Roms

If you buy the ROMs from the respective rights holder, they are of course legal.

Everything else is forbidden.

Downloads from ROMs are not legal unless they are officially offered or sold by the rights holder.

There are also various fairy tales about it - e.g. B. That it is legal if you own the game in the original. Unfortunately, this is complete nonsense. In this case, it would only be legal if you took your own game and read it out personally in a ROM.

OK thanks

It is illegal for you to download them for free

In the form of nonsense, whether something is offered for free or for a fee is irrelevant.