A couple of posts/peeps wanted to know the settings that I used for the reflective lake water in my original screenshot. I didn’t use any special settings other than tweaking the water material ‘roughness’ to be very low in order to increase the ‘shine’. All other effects were more or less default. If you are not seeing any reflections, it may be due to other settings in your UE4 setup (e.g., post process settings, screen space reflections on/off, different project settings).
In any case, I uploaded my UE4.26 water project to Dropbox so you can download it for comparison: Dropbox - Water_4.26_reflective.zip - Simplify your life
Note that it is an old UE4.26 project, so later versions of UE may have updated the water plugin/materials.