There are quick ways to setup a satisfying dev exp for small teams for full stack apps in terms of what will get you going for a while:
1. Git based CI/CD pipelines.
2. Multiple and arbitrarily configured amount of instances.
3. Easy rollbacks, no off time deployments.
4. Different set of environments. Branch/PR based preview links.
5. Out of the box E2E frameworks, etc.
I do agree however that you need someone in the first place to know that those things exist, but in a start up that would just be one experienced eng who is aware that they exist.
But they are standard in terms of that these are things that 99% of SaaS based Start Ups would definitely want.