Have you tried just googling on "Chicago charity bike rides"? If you do so, you will find at least one that is taking reservations pretty soon.
Le Tour de Shore at BikeReg.com registration opening 2/7/21
cowaLUNGa was virtual in 2020 and hasn't posted any information about this year
Two rides are listed now but only one is near Chicago
https://www.bikeride.com/events-loca...linois/#events You might check back on this one occasionally to see if more rides show up.
Busse Woods Night Ride at 12 miles this is not much of a challenge.
It's pretty questionable that any mass gathering like a charity bike ride will happen before we get more people vaccinated. Used to live and work n the Chicago suburbs so this question made me curious.