There are only 22 hours and 41 minutes left until Su Xiao returns to Reincarnation Paradise, but he does not seem worried. The reason is simple: his main task is to survive until the end of the Holy Grail War.
Surviving until the end of the Holy Grail War can be understood in two ways. The first is simply surviving, which won't result in a very high overall evaluation. However, considering the number of Heroic Spirits Su Xiao has killed, the overall evaluation won't be low either.
As for the second way, it involves artificially accelerating the end of the Holy Grail by summoning it within the 11-day limit.
If Su Xiao did not engage in mutual damage with Blood Gate in this world, he could achieve this. But he first had a life-and-death battle with Blood Gate before seeking other Heroic Spirits. The 11 days were mostly consumed in the struggle with Blood Gate, and now the remaining time is clearly insufficient.
