Try and do the same if you can. Leverage what skills you've already gained to switch into a career where they are a big advantage. Then you are starting nearer to those already in the field, not the beginning.
Absolutely. In many cases, there are often a wide range of related/adjacent jobs that are significantly different in various ways but can nonetheless be a fairly natural transition. (Though key word can. I've seen examples that worked and examples that didn't.)
On the other hand, I'll go back to school and get a Masters degree in this very tangentially related STEM field is probably going to be a lot harder.
And even if harder, wouldn’t it still be a productive means towards the end of moving into that field?
And, sure, if you want to change to a completely different area with much less overlap, that's not to say you shouldn't do so. But I certainly couldn't walk right into an unrelated engineering job at this point even if it were related to undergraduate coursework. In fact, it would be probably be easier for me to do a software job today even though I did essentially no programming in school.