Not necessarily. I think it's broadly correct. But I just went through my ChatGPT experiments and I'd say it's roughly two thirds with spaces around and one third no space. Especially when contrasting and with relative clauses, it doesn't do any spaces. But I heard they're messing with it anyway and stuff like that changes all the time. Seems to me modern ChatGPT uses less em-dashes altogether, compared for example to half a year ago?!

I've been using them since before AI...

Yes, I do. It's just that since AI has come about the use of m dashes has exploded.

It's entirely possible for someone to use m dashes by themselves, or just maybe to use an AI powered translation or grammar check app, and that's fine.

But because I work with AI a lot "m" dashes, the term "load bearing", the "that's not just X, that's Y", etc. ways of speaking just signal heavy AI use to me. And usually the fact that I notice them and the author of a news article or post or whatever didn't, makes me suspect that the output was not re-read before posting.