I have had chronic back pain since my twenties because I have really bad scoliosis (my scoliosis has scoliosis, so to speak). Curiously enough the two chairs I can sit for prolonged times without drowning in pain are two cheapish IKEA chairs.
I have an IKEA Markus at my desk. When I bought it I preferred it to every other chair I tried out regardless of price, because it exactly fits my size and proportions. I like it more than the three times more expensive office chair with myriads of adjustments I have at work. If you don't have the exact right body proportions it is a really crappy chair, but for me it is perfect. I have to shuffle around and move my position every ten minutes, but I can sit in it better than any other desk chair I ever tried.
But I don't play Elite at my desk; I play in VR exclusively, and my pilot's seat is free standing in the center of my office. It is an IKEA Poäng, and it is hands down the most comfortable piece of furniture mankind has come up with. I have played six to eight hour sessions in it without feeling a thing or ever having to move my position. As far as I am concerned, it is a miracle.
I would never buy a "gaming" chair like the Secretlab ones. For one, the pseudo-rally-seat look most of the gaming chairs offer looks ridiculous, and my impression is most of them are not worth the "gaming" premium. SecretLabs seem to be very popular/have very high visibility because they push very agressively though "influencers" and content creators, but I have no idea if they are worth it. I doubt it though.
Go out to local office suppliers (or even IKEA) and try every chair you can and buy the one that fits your back (if you can afford it). It is annoying and takes time, but probably less than ordering, trying out, and sending back chair after chair.