I also use the autonomous ergo pro. Or 2. It’s the green one. I absolutely love how customizable it is, and it’s got some amazing lumbar support. I had a gaming chair at the start of the pandemic, and my back was in so much pain by the end of the day.
It’s much better now.
I don’t think much can compete with the Herman Miller Aeron, but if you can’t find a good used one nearby, the ergo would be my next recommendation for sure.