I've never gotten sulphur burps from Sema, but I used to get them out of nowhere every few months or so. I still have no idea what was actually going on, but basically I would randomly get super, ridiculously sick for a couple days. I would have the gross burps constantly, heartburn up in my throat, and be throwing up bile.
Obviously it's a different cause, but the only thing I found that helped was just straight up not to eat. :l Understandably that's not great, but especially when it was happening consistently, I would pretty much go on a water fast for three days or so until they went away. The nausea was unbearable and I literally couldn't work when it was really bad because I'd still be throwing up even if I only drank water.
If they're really bad, maybe try protein drinks and electrolytes and see if that helps? My manager at work was also convinced I had something wrong with my gallbladder because she had the same symptoms before she ended up in emergency surgery to get hers removed.
The weird thing is, I haven't had these problems since about a year after I started semaglutide, and they'd been an ongoing thing for maybe five years prior to that. I feel bad for anyone suffering with any of this stuff, it's definitely uncomfortable.