Let me play devil's advocate and suggest you consider staying, despite the good advice otherwise.
Only one thing is required to get a blackbelt: not quitting. Mat time will take care of everything else. Therefore, the *most* important thing about a gym (as long as it has a legit instructor, which I assume yours does) is whether you feel like quitting when you train there.
Since you seem to like the gym and have progressed well, maybe the vibe of the instructor or the gym overall is one that is compatible with your personality. I've trained at a lot of gyms, some with awesome blackbelts, but just because the instructor is famous or a badass (as well as badass training partners) doesn't mean it is fun to train there.
If you are having fun and making legit progress, then you are moving towards your eventual goal. If you switch and end up not having as much fun, for whatever reason, and end up quitting, then the switch was not a good idea.
There are plenty of ways to challenge yourself with lower belts, including working on defense, just using one arm, trying new moves, etc. There are probably dozens of threads on that topic on this forum. Legends like Marcelo, Braulio, and Rickson all trained for extended periods with lesser partners but still stayed sharp and grew. It's all in how smart you train.
I used to feel a little like you, I was the only bluebelt with a bunch of whitebelts. Fast forward a few years, and now I'm an experienced purple and those whitebelts are on the verge of getting purples themselves -- and they are tough as can be. They all know my game and challenge me every roll. Plus, I feel I had a part to play in their development, which is nice. The most important thing is I have continued training and having fun.
You might want to visit the other gyms and see how you like them, but don't quit your gym without taking into account the vibe of the gyms.
To sum up, try not to forget the big picture just to advance more quickly in the short term.
Only one thing is required to get a blackbelt: not quitting. Mat time will take care of everything else. Therefore, the *most* important thing about a gym (as long as it has a legit instructor, which I assume yours does) is whether you feel like quitting when you train there.
Since you seem to like the gym and have progressed well, maybe the vibe of the instructor or the gym overall is one that is compatible with your personality. I've trained at a lot of gyms, some with awesome blackbelts, but just because the instructor is famous or a badass (as well as badass training partners) doesn't mean it is fun to train there.
If you are having fun and making legit progress, then you are moving towards your eventual goal. If you switch and end up not having as much fun, for whatever reason, and end up quitting, then the switch was not a good idea.
There are plenty of ways to challenge yourself with lower belts, including working on defense, just using one arm, trying new moves, etc. There are probably dozens of threads on that topic on this forum. Legends like Marcelo, Braulio, and Rickson all trained for extended periods with lesser partners but still stayed sharp and grew. It's all in how smart you train.
I used to feel a little like you, I was the only bluebelt with a bunch of whitebelts. Fast forward a few years, and now I'm an experienced purple and those whitebelts are on the verge of getting purples themselves -- and they are tough as can be. They all know my game and challenge me every roll. Plus, I feel I had a part to play in their development, which is nice. The most important thing is I have continued training and having fun.
You might want to visit the other gyms and see how you like them, but don't quit your gym without taking into account the vibe of the gyms.
To sum up, try not to forget the big picture just to advance more quickly in the short term.