I think this is post number 5000 for me. So I may as well use it to take on some things...what's a beginner, intermediate or advanced aquarist? I ask because I think the fish follow the aquarist.
A beginner has fish because they are pretty, and tends to depend on others for information about them. They are at the pure consumer phase - fish die, fish get replaced. They haven't made many mistakes yet.
If they are on this forum, it's to ask 2 or 3 questions, and then to ghost. They like their tank, but they don't really commit to making it work. That may come in time, or the tank can be heading for a garage sale.
Intermediate comes quickly, sometimes right after you start. It's an attitude, not a skill level. If you're reading this thread, you are at least there. You decide this is interesting. Fish, plants and even snails interest you. You may not have made all the mistakes yet, but you will because you venture out of passive fishkeeping. When you do, you want to grasp the reasons, and don't just see it as an opportunity to get new fish. The ones you have begin to matter. And the people like you who keep fish begin to be very interesting to talk with. You read about fish here, and in other online sources. You join a fish club and go to meeting where actual human beings can become "fish friends".
You may lack skills, but it begins to dawn on you that changing water is a simple task. Reading about fish to keep them appropriately is enjoyable. Overfeeding is bad. Live plants are neat. This hobby seems to have secrets for experts. Seems to. It's actually deceptively easy.
Advanced? You set up biotopes after research, and you have enough experience to troubleshoot. You may try some fish you consider difficult. You may succeed with them. You probably breed fish, at least sometimes. You read about fish. You begin to formulate projects and they work well. You can talk fish with people, and not just listen. You can change your ideas.
If you love white clouds and want to pay attention to how they are kept, they will be easy. You have to buy healthy ones, do what is needed, and enjoy. But a lot of the fish you'd consider intermediate will be the same story.