Unless you’re just reading from a screen or watching videos / in a meeting I think it’s quite hard getting used to actually ‘walking’ while doing anything that needs concentration. Reading a book on a stationary bike is hard enough! I think just standing is a good half way option, putting computer on a higher counter. You may find a cheap manual treadmill (I don’t think you’d need a motor driving the belt, just mechanical), and could start with that.

Have you seen the little object with pedals that sits at your feet? KMart sell them. Is this what you’re meaning?

When I worked full time, office work also, I would go for a walk at lunch time.

I’d consider talking to an Occipational Therapist or Physio about the best type for your height and posture as they’ll know what supports you the best.

Also, I time the movement breaks and vary the cycles.

I schedule in lots of movement breaks but do not have any equipment, only my legs!

Sorry, have no advice. Success finding what you’re looking for !

I didn’t know this was a thing. I have trouble just hitting the buttons on my phone to get my podcast going while on the treadmill so I’d be hopeless at working effectively lol. Good luck, I hope someone has the answer.

Sorry no answer bug really interested in others answers