Besides, it hasn't been only once that an actual size for Seireitei has been brought up in-source before here in this thread but it's been ignored for...reasons (because pixel-scaling is done when there's no hints of an an size for something and it has to be estimated).
You mean the 200 miles movie thing?
If i were to sum it up the entire battle between all these characters were fighting in Seireitei and the Royal Realm. Like if you say all these captains and sternritters and espada are country level but ignore the battlefield was confined to what we see as a city (Seireitei) and at most a medium sized country, it's insane to suggest that the weakest of the major characters are captain level and that anyone is doing stuff at galaxy or universe scale energy output.
That's standard shonen powercreep where the stakes get raised every arc.