OP's article is from a crypto blog and I think it misses the big picture.
The Spectator [0] is imho more enlightening:
There has been speculation that Durov’s arrest is linked to his most recent
trip to Baku, Azerbaijan, where he reportedly attempted to meet with Vladimir
Putin during a state visit last week. In recent weeks the Kremlin has begun
suppressing access to Youtube and WhatsApp in Russia in the wake of Ukraine’s
Kursk incursion. There is speculation that Durov may have been attempting to
persuade Putin to leave Telegram alone – but the Russian leader refused to meet
him. The fact that Durov flew from Baku to Paris in his private plane, knowing
that the French had a longstanding warrant out for his arrest, is one of the
unanswered mysteries of this story.
So it seems the mystery has a reasonable explanation. There are lots of accidents in Russia, and Pavel probably chose France as the safest option.
There are now also rumors that Russian officials got instruction from above to delete all their communication from the platform.
We will have to wait for more information.
EDIT: I will add that Pavel already lost control over VKontakte in 2014 to the state. By then he had already started Telegram, and so he left Russia back then. (Being denied a meeting with Putin gives Prigozhin saga vibes.) I think he knew the net is closing.
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0. https://www.spectator.co.uk/article/the-arrest-of-pavel-duro...