[lmilcin]

I feel your pain, I am in much the same situation just in a tech lead position.

It takes a lot of patience to undo this damage and explain that simplicity is much more important than lazily, mindlessly repeating "best" practices. I am using quotes intentionally because they aren't actually best -- "best" would suggest there are no better practices which obviously cannot be true.

The goal should always be to make the application simple and easy to work with. Patterns should be tools to achieve the goal rather than being goals themselves.

Simple is important because it allows understanding your application (which is important for developer efficiency as well as improving reliability). It also enables you to modify your application much more easily (more code usually means more work to change it) and this is important to fighting technical debts and to reduce cost of any future development.