I used brilliant for a while to see what it was like and tbh if you have the time to use it regularly and the money to spend, I thought it was worth it. I just don’t have the time to make it worthwhile right now.
I learnt a lot in a short space of time and it kept my attention well, which can be difficult given I have adhd.
I’m sure there are better, more in depth, apps or websites somewhere but I found the game like interface to be much better for me and much more interesting