I've been working from home since 2017. Had a brief (scary) ulna neuropathy (nerve issue in arm) where when you're arm is constantly pressed against the edge of your desk or laptop and causes the pinky and eventually more fingers to go numb.

was diagnosed and recommended surgery... said eff that i'm too young (was early thirties at the time) and landed on switching to a standing setup. within 2 weeks of giving my arm relief, the neuropathy disappeared and hasn't come back since. i've convinced many at my company to switch to a standing setup and miraculously the health problems started to dissipate.

eventually i had a similar thought as you. what if i could get steps in WHILE working?!? i bought 2 under desk treadmills to try, both were fine and with noise cancelling mics, no one could hear the subtle whirring.

since we're a fully remote company, i have some coworkers that would complain that THEY were getting motion sickness looking at me as i walked in our meetings. returned the treadmills after that. fwiw - i ended up training for an ironman and got an indoor bike setup for winter training - no one complained about motion sickness with that. =)