Unit tests and code coverage is anticorrelated with success. With a startup, your goal is to iterate the fastest. You cannot afford to be spending more than 1 day of time on your continuous deploy system before you have your first paying client.
Given the size to your team, you should also have been spending near zero time on documentation. Documentation should be in the form of sticky notes and Slack messages.
I think you’re very talented technically, but you should not work on startups until you are able to emulate more of the successful technical cofounder patterns.
If your code and processes can scale to 100x of your time expected volume, this is almost universally a sign that you have failed to optimise for what matters.
This also goes even if you’re building something like AWS. AWS engineers do not build over-engineered systems that can handle 100d of its expected volume.