Flytenow would make this a more attractive proposition by agreeing to pay my attorney fees if the FAA takes action against me because of a Flytenow flight. That would include representing me before the FAA in administrative proceedings and in federal court as far as I choose. (I'm a private pilot, not a commercial pilot.)
Better yet, because I'm not aware of the funding behind Flytenow, put the estimated maximum cost in escrow with a trusted third party such as a bank so it would be available even if Flytenow runs out of money and ceases operation in the middle of the litigation.
Then I'd be more likely to try it, and as an additional benefit the FAA would be less likely to pursue Flytenow-affiliated pilots. (FedGov agencies would rather try to make a test case, all else being equal, of citizens lacking aggressive legal representation.)
It probably can't be bought. Most insurance relies on there being some kind of probabilities associated with different outcomes, and that the insurer can sell enough policies such that they capture the law of large numbers and the idea of an expected outcome is valid.
If Flytenow wants to cover this, they're going to be self-insuring and the policy is only good as far as the company has cash or credit to pay legal bills.
I guess it would be hard to underwrite something which is essentially a legal opinion, but there are underwriters who will do weird one-offs. Generally it's based on being able to reduce it to well-known probabilities, though.