How to get deeper into crypto

Been in crypto since 2021. All I’ve ever really done was bought and held through coinbase. It’s been good for me since I didn’t understand much of how everything worked on a deeper level.

Now, however, after years of learning about it and the urge to get deeper into it I have developed an interest in buying crypto that has a much lower market cap and alt coins not listed on mainstream exchanges. My question is, how do I do that?

I’ve read a bit about uniswap, and at first I thought that that was just a normal exchange that I could trade any coin I wanted on it. Yet, after looking into it myself it doesn’t seem to operate that way and seems like you have to have ether on it to buy and sell and can only trade coins on the ether network… Or something, I really don’t understand it all. Every time I do research on Google it just gives me some boomer article about the top crypto exchanges to trade on, and that’s not what I need. I want to trade the underground alt coins that I can’t get anywhere else. Can someone explain this to me like I’m 5 and tell me how to do this?