I haven’t seen any company that can offer anything like that: the no fixed address (and I would assume that means no taxes paid to the government for a national health scheme) would mean most travel insurance policies would be void.

Pretty sure you’d need to look at international health insurance, not travel insurance.

The company that will allow that will be rich soon

We use World Nomads. You’ll use your “home” address. And you can buy a year at a time and then renew while on the road. No need to return home first. We’ve filled 3 clams with them, all paid in a reasonable amount of time, the only catch was that we had to have the checks shipped to our home address and put in our bank account from there. I asked them about this, they claim they are working to update to direct deposit but I don’t know if it’s happened yet. As far as an insurance company goes, they are the best I’ve found that understand digital nomads and full time travelers. Chris, the owner, is amazing and travels almost full time himself, so he gets it. As far as electronics, they cover up to a certain amount. But you can purchase just electronics coverage that will cover you anywhere in the world.