Diversifying your portfolio is a good thing to do
You have Binck, a subsidiary of Saxo Bank, perhaps the cheapest in the EU but I'm not sure. You have also Degiro, Trad Republic, and Trading212 good for us
By the way, non-U.S. citizens living outside of the U.S. can open an account with a broker there as long it accepts applications from your country of residence and uses SEPA (since in the EU, we use SEPA) Just to show you, you're not limited to EU brokers.
One I don't recommend is eToro, I could write long stuff about it...
It's up to you to check the fees, the minimum investment (if there is), the UI/UX, and other stuff
@OP isn't looking for a way to buy crypto in Europe, he's looking to invest in the stock