I always have either three or four carry-ons.
One is the bag I mentioned earlier. The scond is the backpack I have on the rear of the seat. It has my CPAP, all medications (including syringes), a blood pressure meter and blood sugar meter. So these two are 100% medical and exempt from limitations.
If the trip is aonly a couple of days I will not check luggage, so I will have a maximum size rolling suitcase, and my last piece will be my computer bag with reading materials.
I have had airlines initially attempt to limit my carry-ons, but once I let them know that two are 100% medical equipment and supplies I have had no problem. And, of course, since I am parking the
ECV at the aircraft door and one of the first to board I always cedn put everything overhead.
And if you are going to remove the arms from the ECV, wait until you have gone through Security.