How do you gamify a SaaS? (I will not promote)

Some sites; specially AI related, gamify their services by giving credits as freemium plans and making the UI/UX more fancy like a game rather than a service.

How do you gamify a B2B private SaaS? eg. CRMs (common example)

I'm looking onto ideas to gamify it to make my customers wanna stay more in the app and pay more to unlock services rather than paying a fixed price to make it look as a 'freemium' or 'pay-as-you-go' more liberal system.

Looking for fancy ideas to implement! Thank you

Disclaimer: I will not promote