Hey man, I started with an office chair and worked my way up to a rig, the best option is to do that, try and get a sturdy, well priced rig like the nlr f-gt or any aluminium frame cockpits. But if you have no space or want to stay as you are then it’s totally fine, one of the methods I used was putting one of those mouse- arm rest things behind the Bery back wheels on the chair, or you could always place any object that will prevent the wheels from moving/sliding back. Hope this helps and have a good day man.

If you have a 3d printer, this is what I used.
https://makerworld.com/en/models/1044697-desk-chair-brake?from=search#profileId-1030275

If you don't have a 3d printer, can probably find something similar on amazon or at your local big box office supply store (Staples, Office Max, etc)

A wheelstand sounds perfect for you then. Something like the NLR Wheelstand 2.0 would serve you well