There is a lot of contractors and you have to be extremely good to do what the dude/dudette said.

Like - have a unique skillset, have multiple certifications, recommendations, proven B2B experience as a consultant.

Then getting contracts is easy. Probably less easy now tho.

I contracted for the better part of a decade and I wasn't extremely good, but I was solid technically and trusted as a problem solver, so I got my first contract from my personal network, and then built it from there. If I had to rely on being extremely good and going in cold I'd still be looking. Your best bet is to go with a third party and then eventually go independent once you have your own reputation and network.

Second this, I’m full-stack with experience on everything from embedded firmware to frontend. I’d really like to try this route, but I’m not sure how to get in the door.

Lets talk. I have recently started consulting focused on data analytics. May be we could collaborate.

Feel free to reach out! My email is my username at protonmail.com