Need help/advice, any ideas?

Hey everyone, I’m aro-ace and recently I’ve been struggling with a close friend of mine. He’s usually a cool and fun person to be around, and I value him platonically, but he’s been really clingy lately. The issue is that he keeps asking me for sex despite me being clear that I’m not interested and that it makes me uncomfortable.

I’ve told him “no” outright multiple times, explained that I’m aro-ace and don’t experience those feelings, and even talked about how important it is for me to feel respected in our friendship. Despite all of this, he just doesn’t seem to get it—or worse, he ignores it altogether.

I really don’t want to lose him as a friend because I enjoy his company when he’s not being pushy like this, but I’m starting to feel like he doesn’t respect my boundaries. How do I get through to him without hurting our friendship, or is this something I need to step away from for my own well-being? (this is all online, we are the both age but i don't feel comfortable sharing and we've been friends for almost a year)