Sniper Elite 4 is for me the closest to hitman sandbox levels. You can approach every level in the way you prefer.
You can go for unseen "Ghost kills only (which comes close to “Silent Assassin” Rating) or just clean the whole map, do all secondary, Melee only, you can set your own challenges that fit your playstyle .
It’s also possible to speedrun the levels with a good plan, lot’s of different and unique approaches possible.
You have a huge arsenal of attack possibilities and combination:
Pistols, SMG, Assault Rifles, Panzerfaust, LMG, Melee Attacks, Stealth Melee attacks, Granades, TNT, 3 trap types,
Enviroment allows Explosion accidents, falling objective accidents and distractions
Sniper Elite 4 is a bit like Colorado. There are nearly no civilians, only armed guards. So one mistake or missed shot can bring you in trouble. You can hide in foliage, crouch or lie down to minimize the radius of getting spotted (which is very nicely visualized in the mini map). In night levels or dark rooms you can shoot lamps/light sources for the same effect.
There different ways to lure and kills targets:
Shoot lamps, generators, throw a stone or whistle, let others find a dead body to lure a group for a multi kill granade shot, shoot the granade on belts
You can use silenced or unsilenced ammo for pistols and rifles
You can soundmask your shots with envormental noise (broken generator, a canon shooting, planes passing, explosions and many more)
Triangling: Shoot a target loud, change position, shoot target 2, change position,… to confuse the enemy.
SE4 controls are pretty close to hitman and you also have 3rd person view.
The more you play the game and come back the more interesting it gets.