When I worked for Public Works in SWFL, I ran the camera truck for a while. I saw many sink holes. There, it was always a pipe failure.
I know you're rural, but, is there a catch basin in the right of way ? Is it possible there is an outfall pipe going into a sump ?
I'm in Citrus Springs, and there are a lot of sumps here. I see drainage pipes going into them. If so, it could be old CMP ( corrugated metal pipe ) that rotted through.
Do you have a probe ? Basically a length of round stock with a "T" handle on it. I used to poke around the sink hole, and see if it hits something. Or if I hear a metallic sound.
I would be concerned. Maybe there's a contractor with a pole cam that could look into the hole. Not to sound like a dick, you may want to check if your homeowners insurance has sink hole coverage.