In Infinity War Ross directly asked Rhodes to arrest Captain America and the others and promised punishment when he didn't. This was after Thanos already invaded and the Avengers were reuniting.
You're acting like nothing changed by the time things hit Endgame. Ross was snapped and wasn't even around. At the end of that movie he was at the funeral which shows his opinion on the matter changed.
During and before Infinity War was another story. Ross and the people who enforced the accords were still on their power trip. If Tony, Nick or whoever else ignored him he'd have the right to arrest and punish them and he would have done so until the events of Infinity War or any other event that proved to them that it was a mistake.
I HIGHLY doubt they'd have actually done anything, sorry. I just don't believe it'd be anything beyond harsh words and false threats. ---
"And no I'm not signing your twitter after this type of attitude so don't ask..." - IIINCORRUPTIBLE