In your situation, a realistic behaviour would have been to divert to the nearest airport, and file an IFR flight plan.
You’re perfectly right : IFR means a secure, planned flight, but highly influenced by ATC (slots and all sorts of regulations) and without any freedom (no you can’t turn around this beautiful little lake to see it better).
In Europe at least, ATC are urged never to accept any flight plan (or significant modification) which hasn’t gone through the whole validation process. That’s because a lot of control sectors are often at full capacity*, so if you accept another plane, maybe that’s not a problem for you, but that will become one for the next controller.
The only exception I can think of is approach controllers who can allow an “IFR-like approach”, for training, when they are not too crowded.
(*) at least, before our little COVID problem.