Help me with this health insurance conundrum

I own a small business but have some serious health problems and want to retire. (The business is good and I am confident it will sell, possibly quickly) Currently I get health insurance through a group plan the business buys (group= Me, spouse and one full-time employee). I won’t qualify for Medicare until July 2027. What do I do about health insurance if I sell the business before then?
The group plan will cease to exist with the sale of the business so I don’t think Cobra is an option. I think an ACA plan would work but my understanding is that there is a rather small enrollment period window and so the timing of a business sale would have to be ideal.
Anybody have any suggestions?

According to healthcare.gov, a loss of existing health care coverage due to a change of employment counts as a qualifying live event that allows for you to enroll in a ACA marketplace plan outside of the normal enrollment periods, so it sounds like you should be ok with that route. YMMV and I’m just a schlub on the internet, so verify things yourself blah, blah blah…

Yeah I had the reverse of the OPs situation (left my job to found a start up) and was able to enroll in ACA outside of open enrollment.