What precautions should I take when removing my current fireplace insert and creating a larger gap for the new 3-sided electric insert? Any other suggestions for the overall project?

Hey there! I recently purchased a home with the fireplace in the first photo and I’m thinking of remodeling it to look like the one in the second photo. The new insert is electric, so no worries about gas. I have a few questions:
– Any risks or things to watch out for when removing the current fire insert?
– The new insert is 3 sided and slightly wider than the wall, so we’ll need to create a gap by “cutting” the current sides and extending the width of the wall. Any suggestions?
– Any other recommendations for the project, including the floor or TV setup, would be greatly appreciated. Thanks in advance for any advice you can offer! 🙏🏻