(Spoilers, obviously)

Nothing confusing about TENET at all, huh? In the very first scenes a guy gets reverse shot by a bullet embedded in the side of the stairs of an opera, and the bullet is "sucked" into the muzzle of a gun, and the ugly hole in the stairs goes away.

In our forward moving time: what is the origin of that hole? When did it appear? Has it been there since the opera was built? Did the people building these stairs do that with a big ugly hole in it, possibly with an embedded bullet? If not, where and when did it come from?

The thing is, the whole premise of forward+backwards moving things sharing the same reality falls apart if you stop to think about it for a minute.