Ask HN: How do u host your SaaS technically, and what % of revenue doesit take?

Hello all, I am doing research on how you host your SaaS, including what hosting and third-party services you use. How much percentage of your revenue does it take? No need to publish your revenue, just a high-level percentage of your earnings. I am very confused about what to use for hosting a web app. I know it all depends on various factors, but I would love to hear tips and tricks and also receive resources I can read and learn from. Thanks!