D&R at startup scale = set up billing alerts for different resources. Get a good CSPM. Run Trufflehog every pre-commit.
From there, be disciplined about password managers early, get on at least separate OS logins if still doing BYOD, link up 2FA via Google auth, and figure out your email infra and where the root email that matters for infra is. Enterprise sec up and running.
We have a more local solution to query our security logs.