What is the Bulgarian side to the Balkan and World Wars?

So the standard Serbian perspective on Bulgaria throughout all of these wars is incredibly negative - especially during World War I, which most Serbs think was an utter betrayal and stab in the back from the Bulgarian side.

However, I have never heard the Bulgarian perspective of this (and, by even asking, I’ve probably already angered some Serbs). So if you’re Bulgarian, please tell me: how is history, all the way from First Balkan War, to World War II, seen in your country? Whether it be ordinary layman, nationalist or in education, what is the outlook like? Do you think the actions of Bulgaria as a country were completely justified, that, despite what Serbs like to say, it wasn’t as black and white as “the stab in the back” as this famous picture depicts it: https://www.reddit.com/media?url=https%3A%2F%2Fi.redd.it%2Fvfpewfswufg91.jpg&rdt=33926

I make no pre-judgement or prejudice - I am asking with honest curiosity, as I’ve never encountered the Bulgarian side of this. So thank you in advance for any answer.