The biggest issue I saw with "best practices" in my career is the failure to take into account
who it claiming it to be a best practice, and in
what context. I saw too many junior developers read a rando blog article, then get a non-technical / semi-technical manager excited about something that made their life easier, even though it was by no means a good practice for the context at hand. Or alternatively, believe some vendor carte blanche when they tell you their product somehow follows a best practice.
The overarching problem is that yes, there is software engineering going on in the world, but most organizations are not willing to do engineering. I don't blame the technical staff - they often have good intentions - but rather the typical business is not willing to pay the cost in time or money to do long-lasting engineering practices. This is one of the things not enough of us think about in our career choices - am I going to a place that practices fire drills or engineering?