Ok OP, good to hear you are in North America and in one of the larger disciplines! It sounds to me like you have found your way to the more expensive and high end of horses, even for your area. You might (or might not) be getting excellent instruction on good horses, but if you are trying to run with millionaires on a student budget, you just aren’t going to get very far.
Realize that if you want to buy a horse to compete in this world, you are looking at upwards of $100,000. Then you are going to have to pay thousands of dollars a month to a trainer to keep the horse tuned up for you to ride in one or two lessons a week.
Knowing you are in the USA and in California, traditionally a big area for horses, makes me confident you can find DIY owners if you get out of millionaire’s row and start looking.
You are not going to find a $150,000 Prix St George school master in a focused lesson and showing program for $400 a month but you should be able to find a broke safe horse with a sane owner who is happy to show you the ropes.
It sounds like your riding is more advanced than I assumed! The only ever ridden in lessons bit made me think you could be 11 years old and only riding once a week for the past year :).
It really depends what your goal is. If you want to step back from a lesson only training barn and get some more well rounded horsemanship I think you can find that. If you are really committed to the dressage lesson and competing progression at your training barn, you might not be able to find that outside the program.
Anyhow from the added information I am sure you are advanced enough to go looking for other options!