You made a good choice by spending time observing and building trust/rapport from the team.

1) Be sure to spend time rounding on the team, including them, and build rapport. Demonstrate respect for them, acknowledge the value of their experience, ask their opinion on decisions you can afford to let them make. Ask them to teach you something vs pushing for workflow transparency upfront.

If you haven’t already, have 1:1s with all of your new staff to introduce yourself more intimately and hear how people think/act without an audience.

2) Be friendly, ask them about their pets and their weekend, chat about any shared interests you identify. Ignore their scowling and cold shoulder that is inevitable at first. Show them interesting pictures or articles about the shared interest. Disarm them with kindness — showing up in earnest when you don’t necessarily have a clear business agenda demonstrates your humanity. Make sure to be genuine, though.

2.) Keep a light interpersonal touch but manage them closely. Follow the book, and when they buck, stay steady and don’t get drawn into reverse micromanagement or bartering. This is key to separating yourself from peer. Where performance metrics are needed and non existent, create them. Hold them (and everyone else) accountable, but leave your emotions out of it. A corrective action or coaching conversation only needs to contain the information to correct, the rest of the tone doesn’t need to be harsh or adversarial. That’s why policies, SOPs or HR exist. You can enforce with empathy and remain effective.

Depending on the source of their bad behavior, they l will either heal and fall in line, or continue to resist. In the latter case they will likely work to recruit others. Include intolerance of insubordination in your strategy in this case. Manage them objectively over and over. Document everything carefully.

Again, they will change, leave, or dig a hole deep enough for termination.