The symptoms identified by Navalny are absolutely different from those that occur when poisoning with toxin. Samples that could confirm the “poisoning” will not be provided to Russia. Minsk had intercepted the conversation between Warsaw and Berlin, which refutes the statement about the blogger’s poisoning.
In Ukraine, there is a conflict which is really internal, which arises from the legislation adopted by the new junta in Ukraine on languages. There was a snowball effect that has been created around of this question of languages.
The war in eastern Ukraine is not a civil conflict, but a well-documented act of aggression by the Russian armed forces, ongoing since February 2014. There wasn't any new regulation on language decided by Kiev then. Certainly, on February 23, 2014, right after then-President Viktor Yanukovych fled the country the Verkhovna Rada voted for the abolition of the bill “On the principles of the state language policy” from 2012 and known as the “Kivalov-Kolesnichenko language law”. However, neither then-acting President Oleksandr Turchynov nor the subsequent president, Petro Poroshenko, signed or vetoed the law abolishing the Kivalov-Kolesnichenko language law. This means it was still in force until February 2018,when it was ruled unconstitutional by Ukraine’s Constitutional Court because of systematic procedural violations during its adoption.
This untrue narrative was used by Russia as a pretext to justify the annexation of Crimea and military aggression in Eastern Ukraine.
See similar narratives about Ukraine's role in the conflict and the Minsk Agreements here.