I mean Amazon did this for their mp3s. It was literally just an id3 tag with a unique identifier. Not hard to remove but “good enough” to keep regular people from overly distributing it. You’ll never win against the real Pirate community no matter what you do, so just give people real incentive to buy and actually own.
I still play a lot of need for speed underground on my ps2.
I’ll also always love Carmageddon 2. So much fun and a soundtrack full of Iron Maiden!