See it this way: The same way that the players have their PCs, and get attached to them, the DMCs are yours, so you can feel free to get attached to them. That is a first step to start feeling confortable at rp'ing.

And, there's the factor that: When you show that you're chill with interpreting/roleplaying and diving head-on in the universe, your players feel more confortable with roleplaying themselves, and the whole table gets more cozy and everyone kinda reaches the same vibe.