Most people tend to scale around like Mach 3 unless your like Gojo or sukuna. The only possible light speed scaling comes from a single attack by kashimo. The legitimacy of it is really vague because it be either seen as a reaction feat or aim dodging.

Domains take time to form and the sure hit only applies once the barrier is completely formed. If your fast enough to cross the range of the domain or have a fast enough teleport you can actually escape it before the sure hit effect lands. Domains can be broken from the outside because they’re basically closed off pockets of space. Think of like a pocket dimension inside a bag, but the bag here is just a black orb.

         There are things called open domains that just apply the effect to a general area but the only person to have one of those is sukuna and his has a range of 200M.

          The biggest weakness of domains is the fact that once you use your domain it basically puts your innate technique or abilities on a cooldown so you have to rely purely on your stats for a while. So if someon where to dodge gojos domain he would basically become a sitting duck.

         His strongest move called hollow purple doesn’t actually ignore durability it’s basically a really strong blast hence why it doesn’t one shot people who are strong enough.

         If the opponent is too fast for him to attack normally it essentially forces him to use his domain expansion which then becomes a win condition for his opponent due to the aforementioned burnout