From my experience, it doesn't seem that deltaTime is implemented with blender's physics. I may be wrong as testing this was extremely difficult. Please let me know if I'm wrong and deltaTime is implemented.
Why does deltaTime matter?
Generally, games don't lock your framerate in order to have your game run as quick as your PC is able to. If the framerate is locked, the game will run at different speeds if your framerate is under the cap. To fix this, we uncap the framerate and we implement deltaTime into our code. This way, the game runs at the same speed, and you can run the game at any framerate. If we uncap the framerate and don't use deltaTime, then the game would run faster when your framerate is high.
Why is this a problem?
If deltaTime isn't implemented in blender's physics, then the results would be different at difference framerates. For example, friction wouldn't work properly as someone playing with 120 framerate would take friction twice more than someone playing with 60.
Do I have any idea as to what we can do?
Ofcourse, we can simply have blender implement deltaTime into its physics. Alternatively, (what I tried to do), we can remove blender's physics and code our own physics engine. I've ran into a million problems with this, and I don't think it would make sense to go this way.