Dell U2720Q Monitor
When connected to a Mac I set the scaling so it "Looks like 2304 x 1296". You may need to Alt click on "Scaled" in the Display settings in System Preferences to be able to pick this resolution.
In order to enable 60hz on MacOS I had to enable an HDR mode in the monitor's OSD:
Display -> Smart HDR -> Changed from “Off” to “DisplayHDR”