In D&D turns are resolved in an order determined by initiative, but is this what is literally happening in the world?
Say you have characters Abe and Ben. Abe goes first and hits Ben with their ax. Ben goes second and stabs Abe with their dagger.
If you were in the game world would you see:
Abe attack Ben for six seconds with their ax, and then see Ben attack Abe for six seconds with their dagger
both Abe and Ben attacking at the same time