Exactly this, I’m using my Framework 13 (i7-1280p) for months like this. Temperatures are a bit higher, but that’s only a problem if I run a lot VMs at the same time.
I’ve it in the stand with the hinges up (so basically the other way around as you usally do), because to me it looks like it’s a litte bit cooler this way.
What if you opened the laptop fully, as in 180°. If you then just only output to your external monitor the laptop screen won’t distract you or waste any energy. I think it might even look quite cool as well, with the Framework logo and your choice of expansion cards facing you (especially if you have translucent ones. I do and I love the way they look)
Would that be a possible solution?