Very much this. I bought an Aeron a while back and while it’s comfortable, it’s definitely one size too small for me, the big issue being the depth of the seat. Sadly didn’t realize until it was past the point where I could return it. I assumed that it was just that I’d put on weight since the last time I’d sat on one…

Origins is great, but you’ll enjoy it a lot more if you go back to I & II first as it has a lot of call-outs to that. The version of I & II on Steam is excellent and both games are not incredibly long, I knocked both out in a weekend once.