Yeah, find a urologist, preferably one who knows a good amount about priapism/resources. It can be worth a trip to an ED if it is getting worse, there could be vascular factors or other reasons at play. I can understand the reluctance given a history with an ED, but it can be a damaging condition and pretty painful. But in place of that, and if you are stable, a good urologist may cover it.
A few (many now) years back I had these episodes with general muscle weakness and persistent, long-lasting erections that were unnerving. Eventually for me they said it was some temporary weird reaction off of antidepressants or something, almost like a sympathetic/parasympathetic partial seizure (hair standing on end/ pupils/weakness) but yeah.
Keep going! If you get a bad episode do consider an ED, there could be flow/vascular/other reasons to review in an ultrasound, that could be dealt with acutely, with a shunt or whatever. People get these things and the EDs can deal with them.