Here is a blog I recently read which really resonated with me and I have believe in since I started building small companies/apps:
https://stevehanov.ca/blog/how-i-run-multiple-10k-mrr-companies-on-a-20month-tech-stack
The only small piece I disagree/differentiate on is around the DB component. I am still quite sold on running a SaaS Postgres instance decoupled from the other infrastructure components.