Considering the founder of Telegram more or less had his previous startup VK (Russian competitor to Facebook) stolen by Putin after his refusal to hand over info about Ukrainian protestors [1], and has left the country with no interest in returning, I'd be inclined to trust that Telegram is not a front for the Russian state, quite the contrary in fact.

[1] https://en.wikipedia.org/wiki/Pavel_Durov#Dismissal_from_VK