The risk of accidentially deleting the database is real. However, it can be mitigated without introducing another tool by using a second terraform root module (with a corresponding second statefile). So you would have one terraform root module for foundational or stateful things like databases which rarely change and should never be accidentially deleted, and a second terraform root module that holds only the lambda. The former root module is applied only manually, the latter can run automated in a pipeline.