they make table top easels, that will allow you to put your work at an angle.
They range in price from around $10 -up. It’s also not hard to rig up something with books etc.

with this one the work extends past the edge of the table, allowing you to work on larger pieces, or lets you keep you arm at a lower level.

I would suggest a floor standing or wall mounted easel that will adjust low enough and that your legs will fit under easily when seated.

I use this one with a few modifications to make it more steady as well as able to go as low as touching the tops of my legs when sitting. They do go on sale below the price showing today, every now and then if you aren’t in a hurry. The cross bar in front would probably prevent a wheel chair from getting close enough.

https://www.jerrysartarama.com/saint-remy-studio-easel

I will be glad to share the mods if you end up getting one. You will be able to change the height and angle at will and can get very close to the painting surface with the easel in the vertical position, eliminating all strain from leaning over.

https://www.jerrysartarama.com/saint-remy-studio-easel

Another option, particularly if space is limited, would be a wall mounted system. A TV support would work and is very inexpensive. This one below extends 20 inches from the wall and will fold back against the wall when not in use. Not as adjustable as the floor easel, but a lot less money and should do the job. You would be able to roll right up to it in your wheelchair. To keep it from folding back against the wall when pressing on the painting surface, a simple strap around the extension arms would prevent them from folding, thus locking it in the fully extended position, shown in red (added by me) on the very bottom center image.

All you would need to add is a support board panel where the TV would go. A magnetic system is what I would want to use as shown in the 2nd link below.

https://www.amazon.com/Impact-Mounts-Lockable-Articulating-Bracket/dp/B00P20I33E

https://www.wetcanvas.com/forums/showthread.php?t=1435763

There are several good options at hobby lobby– with their monthly 40% off coupon, it should be nicely priced. I Have several of these, 2 tabletop easels, a drafting table with a tilt top, and a tall easel. I’ve gotten 3 of these from Hobby Lobby although I know you can spend 1000 or more for an easel. I don’t like to spend that kind of money if I can get a workable option for 60$ (Art gets expensive, cut corners when you can).

Table top easels can be extended a bit over the table top then clamped or screwed down to give more reach towards the artist. I use C-lamps when I want the panel close to me and I can’t get close enough under the table.

This TV wall mount has a counterbalanced arm so you can raise or lower it easily, plus the front bracket rotates! $59 delivered. Like a poor man’s Windmill Easel (just the windmill adapter is $265).

https://www.amazon.com/VIVO-Counterbalance-Adjustable-Articulating-MOUNT-VW04G/dp/B01H7UWFUI?ref_=fsclp_pl_dp_1

The only problem I am seeing would be how to lock it in place so that it doesn’t move under pressure of your brush, palm or mahl stick. Too bad it doesn’t have locking knobs.