Toggling a scene between day and night settings BEFORE entering Play mode

Hello. I am relatively new to Unreal, and am encountering some issues trying to set up things the way I would like them to be. I am attempting to set up a visualization of a city street that can toggle between day and night, including turning on/off streetlights. Since the intended users will mostly just be loading into the scene to take a few screenshots, I was hoping to set it up in a way where they never actually had to hit the play button. Instead they would just use the High Resolution Screenshot option, and toggling the scene between night and day would be done with a bool variable attached to a sort of control object. The idea being that when toggled, that single DayNight bool variable would swap the visibility of all streetlights from on to off, and alter parameters of the scene lighting. Is this even possible to do, or should I re-focus my design plans onto doing this within a game setup?

It depends if you want baked lighting or dynamic lighting. Baked lighting looks better than dynamic lighting but it needs to be baked. So to have 2 lighting scenarios you need to bake the lights twice. Have a look at this here

For dynamic lighting you could indeed just use a switch to turn the lights on or off. You could possibly use this here