Ask HN: How come there is no example code for B2B-SaaS apps?

Ask HN: How come there is no example code for B2B-SaaS apps?
I'm truly baffled! There are probably 1000s of consumer (B2C) SaaaS example and OSS apps in virtually all languages. But there is virtually ZERO examples or OSS projects that talk about B2B multi-tenant apps! The worst part is that even companies like Google Cloud don't provide an example. What I'm looking for is: A SaaS app that allows people to create tenants (companies), and allows admin of the tenant to login and manage group of users, keep track of billing for each tenant, have super-admin who can access any tenant. But the rest of the app code is shared across the tenants. I'm looking for code that's either in Java or JavaScript(NodeJS). Are you in the same boat as me? If not, could you please point me to something? I really appreciate that!