Last project I worked on was a mix of on prem software and cloud software. The cloud counterpart had 600+ mongodb databases split amongst 3 Mongo clusters. Th

Last project I worked on was a mix of on prem software and cloud software. The cloud counterpart had 600+ mongodb databases split amongst 3 Mongo clusters. The integration team took usually 2 weeks to setup the on premises software, and the cloud stuff took about a minute. The entire setup for the cloud was a single form that the integration team filled in with data. The point I'm trying to make, is that if your customers require separate infra, they can wait a bisuness day to be setup. Meanwhile they can play on a sandbox environment. It's also doable in fully automated fashion, but you will have to have strong identity and payment verifications, to avoid DoS, and in those cases usually contracts fly around. That's for the b2b side. For b2c, usually you rely on a single db and filter by column ID or similar, which can easily be abstracted away.