Just like in OTB chess, there is no way to prevent the opponent from offering a draw. However, you can report them for spam or poor sportsmanship if you keep declining the draw offer and they keep harassing you with them:
https://support.chess.com/article/209-how-do-i-report-someone
When I'm personally in this situation, I don't even waste time pressing the decline button - there is a microscopic chance I'll misclick and accept their draw offer. Whenever you make a move in the chess game, chess.com declines the draw offer automatically. Similarly, OTB chess draw offers are only live for that move and if someone moves, then the draw offer is no longer available.
Chess.com, it would be great if you could silence draw requests from some opponents mid game. I'm all for offering or accepting a draw when the game has gone stale but there are people who continue to ask for draws when they are clearly losing. It's pretty annoying. It would be nice to be able to silence that.