This does not damage the RTP of the base game since both bets are independent of each other. It is an RNG based game with standard payouts for the main game but the ability to pay up to 2000:1 for the side bet.
Switch Studios are the developers behind this variation, and their typical stripped back aesthetics are apparent here, so it’s an uncomplicated setup.
It is a classic blackjack variation that comes with a side bet known as Noble Diamonds, although it can pay out even if no diamond suited cards are dealt.