We love small charming villages/towns, pubs, gardens
The original garden using "rooms" is Hidcote, a National Trust property. We love it there, something different around every corner. In mid summer it can get crowded as people come from all over the world to visit it. https://www.nationaltrust.org.uk/visit/gloucestershire-cotswolds/hidcote
Chipping Campden is just a couple of miles away and very scenic.
There are several pubs there but I don't drink so can't speak to the beer.
Bourton on the Water (not to be confused by the nearby Bourton on the Hill) is achingly cute and beautiful but also can get crowded. Nearby Stow on the Wold is a market town. Between the two are Upper and Lower Slaughter. Exceedingly beautiful.
My mother's favourite hill was in Long Compton. Mine is Cleeve Hill. The road over Cleeve Hill is quite steep, with a beautiful view of the Malverns.
Another scenic village is Blockley.
A lovely town on a hill with an ancient bridge and wool church is Burford.
With only a day, you will have to plan, and cut, cut, cut I'm afraid.