Yesterday's avant-garde is today's quaint

Somebody throw me a lifeline please because at this point, halfway through Part II, I don't understand what's going on in Mikhail Bulgakov's "The Master and Margarita." Obviously from the first chapter this is a novel of comedic fantasy, satire, and social criticism - with Satan coming to present-day (1930s) Moscow and creating havoc as he appears in various guises, leading a number of characters to disappear - obviously analogous with the Stalin-era purges - and others, particularly members of the literary community to the mental hospital. Then in Part II we meet a new character, the eponymous Margarita, who is in love with one of the maddened writers; OK so far. The M. rubs herself with some magic oil that the Satan character (I think) provides her and she is transformed into a witch; she hops on a broomstick and flies all around Moscow - the novel is now a Chagall painting I guess. One stop takes her to the apartment building where one of her rival literary critics lives - and she destroys the apartment (as well as nearby apartments of innocent neighbors). Well, who has yearned for vengeance on an idiot critic or a corrupt literary editor? Still - it's no great thrill to read of vengeance enacted in such a surreal and preposterous manner. Margarita then is invited to the "devil's ball," where they treat her as a queen and she meets a legion of famous killers and despots - including a # of people who've poisoned their spouses, as the Pevear-Volokhonsky footnotes explain. But can they explain what the hell's going on in this novel? Can anybody? It seems that Bulgakov at this point is just writing on the edge, pushing his narrative as far into the surreal as he can - and I don't really get the point. I can understand that when The M&M was first published in the 1960s, 25 years after B. wrote it, it was seen as a precursor to the many experimental works with multiple plot lines and unreliable narrators and even magic realism that emerged in that era - but today it feels not avant-garde but quaint, and extremely confusing.