The "new" 2022 - 2023 Bolts have a Level 2 charger capable of 11 kW, and a DCFC (DC Fast Charge) capability of 55 kW. The one at the Denny's you mention would be DCFC.I've seen 2 numbers associated with the Bolt.
11 kW, and 55 kW
So if I hook up my future Bolt EUV to it, will I get 11 kW/hour delivered to the battery, or will I get 50 kW/hour?
How much will get into your battery will vary. Level 2 will almost always put in the maximum kW the station is capable of. DCFC varies depending on the cars current battery temperature, SOC (state of charge), etc.