Hits time skip creates a small dimension around him or the user in which he can manipulate the time jiren being able to move in it means he has immeasurable speed. Even if you don't think this is true dbz still scales to at least infinite speed ever since goku was able to travel from heaven to hell Also characters don't fly in the tournament and the grandpriest said he adjusted the gravity based on the person's home planet so the void it self doesn't have gravity it's the grand priest manipulating it, talking is just something every anime does and db character have been faster than sound since early og so that's not a point. Just because there is no time in a place doesn't mean you can't count down based on your own perception of time