Staying active with a standing desk

Balance board over a treadmill?
What type of balance board? Seems like there are many cheap exercise type wobble balance boards like:
https://a.co/d/f0JBrYO
And the fancy stand-up desk ones that are way more expensive like:
https://fluidstance.com/
But looking at reviews online it seems like the higher end ones are just trying to keep you from being static but don’t really want you to actually be active, for example:
https://www.workwhilewalking.com/balance-board-reviews
Like the way they talk about typical walking pace being 1-2 mph which seems way too slow
Top Under-Desk Office Treadmill Bases | Ergonomic Office Reviews
(On a non flat hike on a trail I’m used to and primarily on my phone doing research into what standing desk to get I was faster. A smooth level treadmill?)
For the treadmill thinking of getting:
2 in 1 treadmill | Under Desk Treadmill + Folding treadmill for home
In that the slight incline would help as to the challenge and the small size would make it easy to move out of the way and store to use my chair and sit. But also thinking the max speed means I can’t even do a slow run so maybe get one with a higher max speed but than no incline. (The cheap small ones that would fit all max out at 12km/hr)

My goal is not to be fit from it and I know this won’t replace any more active exercise, it’s too be less sedentary. But still hoping to optimize it a bit from the bare minimum.

Is treadmill just as good as a balance board?
Would it make more sense to get a cheap exercise style balance board that I know is only good for small periods of time in that the majority of non sitting time will be walking on the treadmill?