I have quite the same problem, and usually we only jump a few fances in the ring and home and then we also use the competitons as an exercise, so on some weekends we don’t go to win but just to do some exercise
If your horse is okay with it, go out and do some work in a flat area of a field that you know doesn’t have any pot holes or anything that can potentially injure your horse during work. If you have an open enough field, you can set up some basic jumps that you can jump over, and possibly even a small course. If you have a small ring, it would most likely be your barns problem to set up the jumps, since it is their fault you have a small ring. If you just wanna talk with the barn owner about some basic jumps in the field, they most likely will do it since it will benefit the barn. But if you don’t have a field, you might wanna look at other barns in your area that might have a larger ring.