It’s never great when I start by saying “I am not trying to be harsh here”, but I’m really not. Hear me out.
It’s great that you got what you needed, but it took quite a lot of cooks in the kitchen. I stand by my original answer, which is that you’d benefit greatly by taking the time to learn a lot more before asking the community for a solution.
The GF is easy as far as laser cutters go, but it still requires a basic understanding of how to work with vector graphics. What you just got a taste of is a topic called “boolean operations”. I’d recommend getting rock solid on your understanding of them before going much further, it will save you from having to ask for stuff like this.
To put it into context: what you were trying to do takes literally seconds once you know your boolean operations (and the restrictions on them in this case, which I include in a minute). You’d have had it done and working in less time than it took you to post your original question. (Heck, in less time than it took me to write this way-too-long reply!
We were all beginners once, really we still kind of all are, we’re always learning new techniques and tricks. Anyway, yeah, booleans, good stuff.
(Oh also: a quick detail:
This was because booleans only work on paths, and when you convert text to an outline it’s a bunch of grouped paths. Jules gave you the right answer, ungroup them etc… but the key here is that the underlying reason is that it wasn’t operating on two paths, which difference requires.
When you try and it fails “silently” it actually isn’t silent, it gives you an error way down at the bottom of your screen. It says “One of the objects is not a path, cannot perform boolean operation.” It sounds like you were close, but that little gotcha is sneaky.
Anyway. Laser all the things!