There's actually a few options, two of which have "Simple"/"Simplified" in the name, so it's really not that bad. The IRS isn't much one for pros and cons so I'd read this NerdWallet page as well. There should be tons of resources, to be honest, as there's millions of self employed persons in the US.

I never had to set one up, but as a single-member LLC, I'd probably look at SEP most closely.