It seems most spaces can’t be built right now, when an actual error shows it says:
Runtime error
Scheduling failure: not enough hardware capacity
Perhaps the lucky ones are those that were built in the time where some hardware capacity was available for them (I’d tell you to try going to settings and clicking on Factory Reboot, but that may only show these errors instead of being stuck building, not that the space would build.)
I just kept hitting Factory Reboot in settings until the errors were shown instead of being stuck building with no logs found.
About 15 minutes after my other message everything went back to normal, you should be able to build a space without problems now.