~ there are over 18,000 crypto currencies in existence as of March, 2022. ~
Imagine all these currencies exist in the crypto space and I new only one (Bitcoin). But that is not withstanding. There is time for me to learn
It should be better if you try to comprehend the basic concept first, like a few things mentioned above by @franky1. Truth be told, only an extremely small percentage of total cryptocurrenices that only worth figuring out. Bitcoin is undoubted should be the initial priority.
If you already know the fundamentals of how cryptocurrenices works, I'm sure you can generally separate which project has legit potency or not since the 18,00 numbers are majorly filled with shitcoins or simply scams.