I might be wrong but I thought opening the menu at all, even totals, is considered a pause for the in-game timer. If that's the case I think using the in-game timer would be way too innacurate.

I'm at work atm so I can't verify this information!

Oh i never checked ressources sorry!

Does the game have a discord?

Honnestly, don't look at splits untill you've completed a couple of runs