So I want to go for a 100% run of this game as my first speedrun attempt; but it's not possible for me to actually hit that percentage in one sitting because of the Grandmaster token that is awarded for completing the Arena

Every time I try to load up a round of that it completely crashes the game to desktop (I've tried validating my steam files, and uninstalling and reinstalling), and the only way I've found to actually complete it is to go into my computer's settings and limit the amount of cores it's using.

The issue with that is that it requires me to restart my computer, which would require the timer to be stopped, and that it tanked the performance of the game to half the one successful time I pulled it off (and that was without having any additional programs like a recording software or livesplit open)

Would it be possible for the run to be validated at 99.9% if I were to artificially add 5-10mins to the timer (or however long the Infinity Stone rush usually lasts) either by starting the timer at that time, or adding a split at the end that's specifically for waiting?