Your footwear should have an impact on your movement speed and maybe other give other effects.
For example, walking barefoot on concrete still gives normal speed, but on dirt and similar surfaces, the speed is reduced to eg. 80%, and even more for mud and more extreme terrain.
There could be other debuffs for walking barefoot on extreme terrain except speed, for example losing stamina faster if you run trough extreme terrain barefoot. Or standing on hot concrete for too long barefoot makes you lose stamina. There are many more possibilites.
Basic shoes or sneakers would provide immunity and give full speed on dirt terrain and similar, but would still lack in more extreme terrains such as mud.
Boots would give full speed and immunity to all terrain. They would be more uncommon and have increased spawns in military locations, but not exclusive.
Another potential idea is that all footwear slowly deteriorates and needs to be taken care of, or another possibility is that footwear like shoes give 100% speed and immunity on all surfaces, but deteriorate when used on extreme ones.
That sounds neat, but only if implemented to a limited degree.
I too am a sucker for realism but simulating shoes is going to be one of those things where Iād be ready to compromise.
I think the stats that should be affected by different types of footwear is durability, sound and stamina.
Boots would have more durability than sneakers, be louder, but preserve stamina well over every surface (for the sake of keeping things simple).
You can chose to change the boots for running shoes, which would have less durability, be much quieter and preserve stamina really well.
Barefoot has no change on durability and stamina, but would prove much quieter on surfaces like grass, mud, sand, dirt, generally soft materials, but be slightly louder on hard surfaces, because you know, human skin tends to flap when it hits something rigid.