One of the things that matters for me when seated at a desk (I also do standing desk) is that I like to be able to have my feet flat on the floor when seated, and then for the keyboard height to be lower than most desks.
If you're similar, and you're considering those powered height-adjustable desks, note the minimum height in the specs of a desk (and that the actual minimum height might be an inch or two higher, due to the top thickness and/or leveling). Importantly, the "3-stage" ones on Amazon go lower than the "2-stage" ones.
You can also occasionally find rare low fixed-height desks. I also once realized that the legs of a university lab's white laminate desks were interchangeable with the legs of matching shorter white laminate side tables. (I quietly swapped a set, under the cover of night.)
On chairs, I don't like armrests in any case, and also, note that, if you have a lower desktop or keyboard shelf, armrests on chairs might bump into it.
If you want to remove arms from a chair that has them, check how well that works before you spend a lot of money. Aerons with arms look like they can come off pretty cleanly. I've had good luck with some more conventional commercial-grade office task chairs. I've also seen office chairs that leave unsafe heavy-duty welded steel frame protrusions out the sides, with corners that could rip into someone's leg someday. Steelcase Leap V2 arms can come off, but not cleanly, so it looks kinda dumb for how much money you spent.