I recommend Aeron chairs. I sit for hours years and it is comfortable. The pellicle fabric breathes and keeps your back and backside happy. They come in three sizes, A, B, C, smallest to largest. There is a sizing chart on the website. They have many options available for adjustable parts.
They are expensive off the shelf, but with all the startups that go bust, you should be able to find a used one. I bought one for my girlfriend for $250 from a person on the Nextdoor app.
My ex-wife worked for Geiger, so I got a deal on mine, with all the options. It’s served me well for about 10 years, and has no signs of giving way.
As the saying goes, buy quality, cry once.
Oh yeah, it’s the Official Chair of Office Hockey.