If you're also the one responsible for writing tests, you can easily churn out even more unmaintainable crap.
In my experience it's not enough to just have them do TDD, because writing a good test suite is hard.
How do you teach these things concretely without discussing specific code? How do you tell if the lessons are sticking without checking their future work?
Aside from that, neither TDD nor DevOps practices will get you idiomatic (relative to internally and externally) code, documentation, non-requirement performance worth a damn, test suites that are any good to begin with, etc. etc.. If you're running through a backlog of CRUD-ish features or whatever maybe those don't matter, though then I also wonder why the need for TDD instead of just a good CI pipeline.
In my experience, I have found it is more productive to coach and mentor developers to adapt TDD and DevOps practices than to vet their code. Instead of vetting their code, I would incorporate statistical code analysis and vulnerability analysis into the build system.