I’ll pitch another angle for you to consider. First thing for you to do is understand what the community of luxury car owners is like where you live. Car owner clubs like the PCA for Porsches, Ferrari owners club, etc. one thing that long time owners of vintage luxury cars are always on the hunt for are folks who can do specialized work on their vehicles, and you could carve a niche out for yourself if you played your cards right, connected with the right people and got yourself set up with the appropriate tools and expertise. Finding club presidents and finding out what the critical service needs are for a particular car would be a good route. It can be very difficult to find vintage parts for Cars, but finding folks who know how to rebuild mechanical fuel injection systems, or tune carbs, or any manner of maintenance can be just as painful for these folks.
Main thing is, the only way to get into these types of circles is to make friends/connections within those circles and learning. I bet a lot of these folks would be happy to speak with a young person who shares their passion for cars. Good luck to you!
Service based businesses make service based margins. There are only so many billable hours in a day and being a psychologist isn’t a scalable thing.