To just leave him to cry

[LurkyLurkerMcLurkface]

I know AIBU
I've been trying to get my 6 month old DS down for a very needed nap for 70 minutes. He is still crying. He is fed, in a comfortable cot and has a clean nappy.
WIBU to leave him to cry. He has occasionally self settled so can do it.
I just can't take the screaming anymore.

DD was like this. I was a total mess. It passes. It passes. I won't give you 'helpful' advice because that made me want to scream.

Put earplugs or headphones in and stay nearby (so he doesn't feel alone/scared but the noise isn't so horrendous).

Huge sympathy. I feel like I'm going mad when mine won't stop crying.

As for naps, I don't think you can force a nap. Sometimes mine likes to scream and throw toys around to tire himself out. I offer cuddles but often he writhes away and wants to play on the floor. I keep a basket of interesting objects handy to distract him.