This idea of easy, worry-free database replatforming strikes me as kind of a shibboleth for identifying people who’ve never done it before. In reality they all have subtle differences in semantics and query optimization behavior that mean that every touch point needs close attention to make sure you understand how the behavior in that part of the system changes (assume it will change) and if that change is acceptable. Thinking abstraction layers can eliminate the need for close attention to a DBMS port is the software engineering equivalent of thinking adaptive cruise control means you can play Slay the Spire while driving to the office.