Hubby solved my cup holder issue for me. We had 2 of these in the shop so I got one installed on my side if the FR3. We screwed part of it into a stud, plastic hollow wall grips for the other side. Works great & folds up out of the way when not in use.
He bought these at a marine supply store.
I put two in for the DW, using both the double sided tape and the screws provided. She has one for her water bottle and one for her coffee and when they are folded up they look like original equipment.