I have converted two older Cannondale road bikes into "city bikes" for both my son and his fiancé (1995 R900 2.8 frame, and a 1998-1999 R300 CAAD 2 frame). Both bikes were fitted with 28mm tires, but I wouldn't go with any larger tires. One bike has "flat" bars with 40mm of rise and grip shifters.

If the Cannondale fits even reasonably OK, I would go with that. The frame will be much lighter and it will be strong. See if you like riding it, and eventually, you can plan to sell it and get something more modern. I first got into road bikes after doing a century ride on a Cannondale hybrid. It was slow, the riding position was too high, and it was just not a great experience, I felt like I had been in a bar fight at the end of the ride.

You can easily and inexpensively change the crankset and chainrings later, and you can even fit a 11-30 cassette without having to change the RD.