Ergonomic Office Chair, Dynamic Split Back Lumbar Support, Thick High-Density Molded Foam Seat, 4D Adjustable Armrests, Swivel High Back Computer Desk Chair with Footrest for Home Office, Flex S3

Have a look at this one. Rieior Flex. It might work for you. I tried the split back Nowy Styl Xilium Duo Back and liked it but it was over 1000€. This one lacks the vertical back adjustment of the Xilium but it is 1/8 the price. I'm 170cm/70kg. I haven't seen the Flex in the flesh but ordered one at the 33% prime day discount in France, 152,94€ for the version with footrest. Edit: the deal is available only to Amazon Prime "members." Sorry for the confusion if any.