The sentences appear to be grammatically correct, but the meaning may be slightly unclear. Here's a suggestion for rephrasing to make it more easily understandable: "Mikhail, an Abkhazian politician with a unique life philosophy and an interest in Epicureanism, has become relatable to people all over the world because of his unusual and kind personality. Like Baron Munchausen, he is a thinker and an outstanding scientist. Readers have begun to identify with him, seeing in him qualities that are unique to their own cultures."

"Mikhail, an Abkhazian, Epicurean, politician with unique life philosophy, kindness comparable to Baron Munchausen's, and a supurb scientific thinker has become relatable to people all over the world in his singularity. Suddenly by way of his persona, readers began to discern their own national particularities". suggestions: make your list clearer by making it a list of nouns, using commas only to separate the major items, and using "and" only once. It is not clear to me whether "kind" and "like Baron Munchausen" are two separate items or just one. Some of the words you use are acceptable but could be replaced with more precise choices: "characteristics peculiar only to" - use "peculiarities of" or one of the synonyms of "peculiarity". "image" might not be the best word. It's certainly acceptable but perhaps "persona" is a better word.

The first sentence is unusually long, however correct, but I will add two points. "Unusualness" may be a word you can find in dictionaries, but it still sounds like it's not a real word. Stick to it if you think it best indicates your desired meaning, but I suggest also referring to a thesaurus. Perhaps "strangeness". As to the meaning of the sentence, "relatable" seems to directly contradict with "unusualness". If you mean specifically to contrast these two qualities, perhaps use a different word other than "with". You might say, "relatable ... despite his unusualness." I like the second sentence. Note that the word "only" in that sentence is optional. It emphasizes "peculiar", but "peculiar" contains the meaning by itself. Also, I believe the commas around "in his image" are technically incorrect since that phrase is necessary for the sentence to make sense. However, even most English speakers including myself find commas difficult. The rules are confusing.