We have a house built in the 80s and had this problem with LEDs too. We tried a bunch of different ones and eventually found a GE one that didn’t flicker.

Knowing your budget would be helpful, they get pricey pretty quickly. I bought a Steelcase Think chair a couple years ago and I love it. Very comfortable, lots of adjustments (armrests adjust up/down and slide forward/back) and it’s held up great so far. Replaced a generic $150 chair I’d had for several years which squeaked a lot. But I work from home and my company offered a discount so I was willing to spend a fair amount.