I'd recommend moonlighting to get a feel for it. It's a good way to test drive without the "sink or swim" pressure. You can get gigs from your network, partner agencies, or Upwork.com. (The pay sucks on Upwork, but it's good experience and you'll build your confidence.)

Another (more risky) approach would be to deliberately work at a 5 or 10 person company. This will give you a feel for how to "hunt for your own food" but still have a team backing you up. (I subcontracted at a few small agencies during year one, just to keep some cash flow going.)

I'm in the US, so healthcare insurance is a big concern. But corporations aren't the only ones who can buy health insurance. Depending on a lot of factors, it costs roughly $500-$1000 a month to ensure a family. Some chambers of commerce have a group plan that you can buy into.

On the surface, that sounds like a lot of money. But in reality, it's only $12k a year. If you are a primo engineer making $100k+ per year, save up over several years and you have 2-3 years of runway to pay for your insurance. The moonlighting will help with this as well.

Good luck!