I have owned / used extensively pretty much what I would say are all the chairs you would want to sit in if you want to maintain back and neck / mitigate back pain:
1. Steelcase leap: my first not-crap chair, bought from an office closing used for like $300, great chair.
2. Steelcase Gesture: decided I wanted to “upgrade” after bringing steelcase to office. Went with a sale online and actually didn’t like it much and returned it, but some people love it. This was also way worth it — the store I used had free returns, paid nothing to try the chair for a month.
3. Herman Miller Embody — went to this after the gesture and use this as at-home work chair. It’s awesome. I don’t know if I like it more than leap. Leap makes you sit up right, like it holds you in the position you want to sit in in order to not screw up your back. Embody is super supportive leaning back but feel like it’s less so sitting upright, but I also game in it, so as an all around at home chair i think it works.
4. Herman Miller Aeron — currently using at work, was super psyched I didn’t have to be the guy with their special chair at the new job. It’s — also a great chair! I think it’s similar to the leap, moreso than researching to death might make it seem. You sit upright in it, if you try to slouch the chair makes you feel it, so you sit back up right and then it supports you correctly again.
If you want to get in on cheaper end, I’d check out craigslist / fb marketplace because you can get a barely-used leap or aeron for 250-350 and the chair is going to be great for a decade. Unless you’re a savant these chairs are very equitable with maybe slight preference differences. If you want more stability with warranty / want to buy new / hit a bonus and want to have fun with some of it, online shops you can do risk-free, try one for a month and exchange for a different one if you don’t love it.