~snip~
I've bought coins since around 2019 but I do not know too much (mostly buying ada, xmr, eth, btc).
No offense, but if after almost 5 years you don't know more than you did then, do you think there is a chance that something will change in this matter or will you ask a similar question sometime in 2028? It would be logical if you learned at least some basic things, and only then invested - although it is good to have a hardware wallet, regardless of the bad reputation of that company.
What would you tell your younger self to learn this space efficiently?
I would tell myself
"buy more Bitcoin" and
"stay away from all altcoins" which would definitely be the two best pieces of advice I could give myself.