Ben Platt is nothing like Evan Hansen in real life. Just because both the actor and the character may have anxiety doesn't mean that Platt is essentially playing himself. Rachel Bay Jones and Jennifer Laura Thompson are both mothers; that doesn't mean that they're playing themselves either just because their characters are also mothers.
"You travel alone because other people are only there to remind you how much that hook hurts that we all bit down on. Wait for that one day we can bite free and get back out there in space where we belong, sail back over water, over skies, into space, the hook finally out of our mouths and we wander back out there in space spawning to other planets never to return hurrah to earth and we'll look back and can't even see these lives here anymore. Only the taste of blood to remind us we ever existed. The earth is small. We're gone. We're dead. We're safe."
-John Guare, Landscape of the Body