People always recommend bitcoin, Ethereum as well as others altcoins you mentioned, is because those are safe investment than investing on hidden/unknown gem.
It's because they are proven to be the best on this market and not going to turn out as projects that will just take the investors money away.
But if you are willing to purchase low cap altcoins, thats also fair although much expectations should be controlled. In my opinion, you can have a look and investigation with arbitrum, axs, sui as well as cake. I think those are still low cap and will perform good in the next bull run
Those aren't low cap coins, they're also good coins that have such market cap already so I don't think that suits what the need of OP and people that are looking for small caps.