You can get very high end office chairs incredibly cheap if you looks used. It’s not hard to all to find Steelcase Leaps and Herman Miller Aerons under $300 on Craigslist, eBay, FB Marketplace, or used office supply stores. I got my Steelcase Leap for $220 and it’s been going strong for over 5 years now.
The gaming mode is still the Steam Client. It’s just the big picture client which has built in additional features when used on a Steam Deck.