We only spent one night in Reims at the beginning of our 2019 trip - yet another place where I wish we had spent more time.
Even though I am officially "churched out", I thought the Reims Cathedral and Palais du Tau, the former Archbishop's palace, were well worth a visit.
The highlight of our visit to Reims was the Surrender Museum, where the Germans surrendered to the Allies in May 1945. It's hard to believe this unassuming building (feels like an old high school) housed Eisenhower's European headquarters.
https://www.historyhit.com/locations/musee-de-la-reddition/
By the time we were ready to eat lunch, most places were closed and we made do at a forgettable place. Then we weren't hungry enough for dinner. But there is no doubt in my mind that there is good food to be had in Reims.
You didn't ask for hotel recommendations, but we stayed at the Best Western Hotel de la Paix and would gladly return.
https://www.bestwestern-lapaix-reims.com/en/