I was doing some research on arenas in England & seems like they're isn't much big ones except for O2 & some in cities like Birmingham and Manchester. Guess with EPL being the popular sport & mostly that, there's not a bunch of big arenas like the nba & nhl have. Then I went into looking what other sports are out there since I know the NFL hosts a few games a season. I did see rugby & cricket mentioned but those are outdoor not arena ones. Did see a basketball one called the British Basketball League aka the BBL which has a completely different meaning on this side of the world. But seems like most of the events are in small arenas whether wrestling or in general.
Yeah, that's the main difference - all our most popular sports are outdoor, so most towns will have a stadium for a football team, a lot will have a second for rugby and maybe a cricket ground too but we don't have a league full of basketball/hockey size arenas for this sort of thing.
The bigger indoor arenas are based around entertainment rather than sport and so they tend to be in the bigger cities - London, Cardiff, Birmingham, Manchester, Glasgow, Edinburgh all have 20k+ seater arenas. Bristol has been supposedly building one for a decade but still not got it done yet.
The Doncaster venue Mercedes wrestled Kanji at is a mixed use sports/leisure centre with a swimming pool and an ice rink that holds youth sporting events, minor comedians and music tribute acts... something like our equivalent of a high school gym over there.
The Wolverhampton venue is a converted steel warehouse from when Wolverhampton had an actual economy, similar kind of venue that will book smaller music acts, club nights and comedy. Not too different from the 2300 tbh, but a little smaller and in a way less major town (if Birmingham is a Philly then Wolverhampton is more like a Scranton).