i think these are probably the best products you can get for a home gym

https://www.rubberflooringinc.com/rubber-tiles.html

you need to know rough size/shape you want and calculate out the interior tiles vs. edge tiles but you can build on it pretty easily. the ones from costco/HD/etc are just not as good (although they are cheaper).

sheet of plywood cut to proper dimension heavy duty carpet runner secured with double sided carpet tape. cheap and easy

Initially used the typical exercise mats sold at Costco or sporting good stores. Those are really thin flimsy, and tear easily.
We switched to regular rubber flooring about 1/2' thick. Initially bought a precut one 36 x 48 for horse stall or trailer. Not that much price difference and way better.

Eventually we now have it on the entire basement floor. Found someone selling it in rolls on craigslist.

I put cheap Amazon Basic branded rubber interlocking floor tiles down in my garage floor. Made a world of improvement!

I haven't had any problems whatsoever, but I will say that typical treadmill/trainer/Vasa use is not demanding at all on the flooring so any decent product should work fine. (As opposed to doing heavy lifting or exercises where you're dragging/moving heavy weights across the flooring.)

I ended up putting it across my entire garage floor, costs <$120 total

I'm personally not a fan of the interlocking-type flooring because invariably sweat and Gatorade will seep between the joints in the flooriing and get trapped under the rubber mat and ruin whatever floor you have underneath.

I've bought a few of these:

https://www.amazon.com/...585673419&sr=8-4

They come in two thicknesses and multiple lengths from 2 to 10 feet. I bought three of them to put under my bike, treadmill and Vasa. After two years of daily use, they still look brand new.

I covered the whole floor of my room with this stuff (put it over laminate wood). Was the best cheapish option I found. The seams aren’t that noticeable.

https://www.flooringinc.com/...mats/tough-mats.html

I think they posted this a day early

https://cyclingtips.com/...g-specific-flooring/