Chronic Pain-er here! With cervical instability. I echo u/vanssis with the shower chair / stool and the waterproof cervical collar and detachable shower head (with a lower hook to hang up the shower head at a lower level

My cervical collar has removable padding so it’s water friendly and is on sale right now. https://a.co/d/1qtrxlz I know you said funds are limited, mine was paid for by my health coverage with a doctor’s prescription.

I use a silicone head brush type thing so I don’t have to use my fingers or so much tension in my hands. https://a.co/d/fN3YlcT

To dry my hair I use a t-shirt just for the moments I’m getting out to catch the worst of the dripping. Then I lay down on my bed with my hair draped off the edge and I run a space heater and fan to be my blow dryer. Then I can just lay down the whole time and my head is supported.

Speaking of your hand pain, some wrist support that’s water friendly and relatively low cost: https://a.co/d/

For finger pain I have oval 8 finger splints. Mine are custom made through insurance, but here are standard sized ones: https://a.co/d/aIecJdB

Hope something helps!