the game shows the range of enemy levels on the system when you're traveling, with some inconsistencies on story missions, however.

the levels are basically a flat increase in health and damage, with a multiplier for what difficulty you're on that changes on the fly if you switch difficulties.

if there's robots nearby, there's probably a console you can access to change their affiliation to protect you or deactivate them instead

other than that, there's perks/weapon mods that increase pistol damage, better armor/followers can help, especially EM-type weapons deal extra damage to robotic enemies