As others have mentioned, you'll want to part ways with the foot stool and look into getting a guitar support. I stopped using a foot stool many years ago and have never looked back.
My favorite suction cup support would be the Diego De Oro support. You can also look into ergoplay. Otherwise I use a Barnett support as my go to, but some folks don't like dealing with having to install magnets inside the guitar. Personally I think the convenience, comfort and ease of use once the magnets are installed is well worth having to go through the process of installing them.
Pillows/cushions can also work and are convenient since they don't need to be attached or applied in anyway. The disadvantage is they lack adjustability and some people have to end up using them combined with a foot stool of some sort.
As far as chairs go, people recommend drummers thrones. You can adjust the height and they have ample padding.
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