Re: What would you tell your younger self to learn this space efficiently?
What did you primarily look into learning?
Technical stuff and the history. For the former, I recommend you to read Mastering Bitcoin and learnmeabitcoin.com. For any questions, use this place and stackexchange. For the latter... I think you're in the best place. 
I've bought coins since around 2019 but I do not know too much (mostly buying ada, xmr, eth, btc).
In my opinion, ADA and ETH are shitcoins. Bitcoin is the best in terms of risk and capital appreciation. If you've bought cryptocurrencies with the assumption to get rich, then you're in the wrong place. Nonetheless, Bitcoin still gives pretty good ROI.