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.