Oh yeah that was me, I sent an ask to @nothorses when he copied my tags but I'll expand here as well:
The current view from medical providers I've talked to is that the relationship between atrophy and cramps is more complex than just "cramps = uterus atrophy, take it out". For example, vaginal atrophy might change the stability of the pelvic floor and make other muscles engage more to compensate. So just getting a hysto might not fully treat it.
Also, cramps aren't necessarily a result of things like endometriosis like some doctors think. A retrospective study of gender-affirming hysterectomy patients [1] found that chronic/cyclical pelvic pain was NOT a reliable endo symptom, because it had a high incidence in patients who didn't have endo. (The reliable indicator of endo was abnormal bleeding). This is important because sometimes gynaecologists can get really focussed on endo or other reproductive health conditions and might not consider pelvic muscle dysfunction as a cause of cramps.
The pelvic floor muscles mainly start at the front of the pelvis and run all the way back to the tailbone. This means that as well as trouble peeing, trouble pooing can also be a symptom of pelvic floor dysfunction (also ✨butthole cramps✨), especially if you don't have any other conditions that could be causing it or you can feel stool getting "trapped" in there. You can get a vicious cycle where straining on the toilet makes the muscles tighten up more. Definitely talk to a pelvic physiotherapist if this is a problem for you; a "squatty potty" footstool may also help.
One catch with looking up info online is that a lot of it suggests Kegel exercises, which are a strengthening move that may not help for cramps and tightness issues. My physio specifically banned me from them. Based on discussions with physios and doctors, my understanding is that the increased muscle bulking from T also applies to the pelvic floor, leaving a lot of trans people with pelvic muscles that are strong but too tight (it's possible for them to be weak and too tight). This can create new issues, or worsen existing ones; some patients don't realise they have an overtight pelvic floor until the bulking from T starts making it painful.
Other things that I tried out were:
Botox injections into the pelvic floor. I got mine done under general anesthetic but you can also get it as an outpatient procedure. Best for if you're getting pain throughout the entire pelvic floor, since they get put in the middle and it can break up "chain reactions" with muscles setting each other off.
Biofeedback. Kind of a subset of physiotherapy, you get given a machine or toy that connects to an app and shows you how your muscles are activating. I have a hard time connecting to the "feeling" of them, so this helps me actively relax them.
Medical cannabis (if you can get it). I used a low-dose 1:1 THC:CBD edible. This worked better than most other pain relief both because it's a muscle relaxant, and because my doctor was comfortable with me taking it as soon as I felt any indication of a flare (rather than waiting until I was "sure I needed it"), so it was easier to do good pain control.
Swimming (if you can) and walking. Some of the muscles in the pelvic floor start at the lower back, run down through the hips, and out the front (hip flexors). These can get super tight if you spend all day sitting. Walking and swimming (esp. front crawl and backstroke) help stretch these out.
Treating my other "unconnected" medical problems. Getting sleep apnea surgery made a HUGE difference to my pain levels even though it wasn't the "cause" of the pain. Turns out that when your body is struggling on a day-to-day basis, that can make your pain conditions worse. Wild.
[1] https://www.sciencedirect.com/science/article/abs/pii/S1553465021000510