I think the scale of your map is very dependent on:
how much movement options you decide give your players
the TTK (Time-to-Kill) in your game
Take well-known shooters like CSGO and Overwatch, and look at some of their maps.
CS, being a tac-shooter where the only option for movement is just walking and running, along very low TTK, results in…
the map generally being smaller, and having several narrow choke-points.
the maps having more corners/objects to hide around.
The map is designed with this low time-to-kill in mind, with various lanes and objects to play around for cover/attacking.
Overwatch, on the other hand, is a hero shooter where Heroes such as Tracer, DVA, Reaper, Hammond have quick horizontal/vertical mobility or repositioning tools in their kits. The TTK is also relatively higher compared to CS. With that, maps tend to…
Have much larger and wider chokepoints
Have more spacious map design
This really helps players to really utilize their mobility to the fullest potential without running into a wall as often.
Ultimately, it does depend on your game’s constraints, but i hope this helps!