There are two ways you can play MGSV: Ground Zeroes. You can do it through the standard edition or you can get the Definitive Experience. I was wondering if there are differences between the two. I submit one run, but I play it on the Definitive Experience.

Is there a problem if I submit runs using that version?

I've heard that the load times on definitive edition are slower than standard. I run GZ on PC that way as well as PS5 console (via PS4 title).

You can certainly speedrun definitive edition for IL's if you're aiming for IGT. For a rull run on RTA, you would have slower loads working against you.