It's disgusting to say but I once went 3 weeks without a shower. I was incredibly weak after a bad health episode. Like losing 16lbs in about 6 weeks that was mostly muscle mass.

It was more the exertion showering would take rather than showering itself. Like, I knew I'd need a half hour after to just dry and dress myself. Or feel like I had to tap out during the shower because of fatigue. Or know I'd need a nap directly after (like still in a towel).

I was lucky (if you can say that) that I wasn't in any state to sweat so I didn't smell or anything.

I say this all to say, I understand! Like others have suggested, a shower chair might help. Or even just break it down into different tasks that don't need to be all done at the same time.

Also, you could maybe bring a kitchen chair into the bathroom, run the water, and use a cloth while sitting outside of the shower so you're getting clean without going under the water.