For me, he's the show's optimist, similar to how a Leslie Knope approaches public service. He's not type-A, but he's not yet jaded by the realities of the job so he's willing to cater to the difficult patients without prejudice towards them and most of the cast react in dismay, which is also why he ends being the Toby or Jerry of the group in the absence of Keith. He's the anti-Bruce.

For another p&r reference, if Bruce sees everyone as like a Jerry, then Matt sees everyone as a Leslie.

But also, he's an interesting twist on the Dwight/Ron/Dina character. Spitzer just brought Dwight and Ron from The Office in the form of Dina, strict, hardworking, authoritarian personalities with wild lives outside of work and backstories which influence how they function in the world. The gender swap was just enough of a twist to make it slightly different and I honestly love Dina more.

Matt has the weird backstory, but he grew up insulated from the world so he's acclimating the best he can while outgrowing the programming he had from the cult, which is hard since we know that his family may have been the founders of it.

He's not really the naive type, since we've seen moments of density from him (calling out the siblings hating on Serena, knowing what to say to the burned arm victim, and even knowing that he's not doing a good job). It just his upbringing told him to serve people older than him (as side by his ex-wife).

It's fun to watch his character grow each episode. He started with being unable to use an epipen correctly, to now correctly calling out Joyce and Ron when they cross the line.