I didn't misunderstand anything, you just didn't explain what you were looking for.
Nitrogen allows you to parlay the spread and o/u for the same NBA game.
No, you DID misunderstand it. It's written clearly in OP. Nitrogen doesn't even have enough player bets. I checked it and they give only 2 bets for players out of 9 games. You can check 1xbit to see how many player bets they offer. I like 1xbit's player bets but I can't make multiple parlays or singles.
Basically I'm looking for an alternative to 1xbit for player bets.
Nitrogen ❌
Directbet ❌