I have suffered from a chronic illness which at the moment has no cure and is only getting worse. I wouldn’t be able to get married and have to support myself financially. I am planning on buying a house to put in rent and get an income from it. However while saving for it hajj would become wajib on me. Would I have to do Hajj first and then come back and save for my house?
(side note due to my health condition performing hajj would be very difficult for me)

No, hajj is only Wajib once you are fully capable. Having a home and income stability comes before hajj. It’s not just money that defines stability.