We too are building a SaaS product with billing over OAuth2. Here is our product page - https://formfly.intuit.com. We are not using OIDC. What are you building @taosx? and how are you using OIDC?
Just dropped my job in order to catch up with everything I wanted to learn and what better way than to build a business.
Currently I'm a bit (1 month) behind the schedule cause I complicated everything in order to learn k8s, rust, web assembly, svelte/sapper...so much fun, on the other side I burned through my finances a little too fast so I might need a job soon.