It's not a leftist history by any stretch and I recommend Keeran & Kenney or Carlos Martinez's article series "Why Doesn't the Soviet Union Exist Anymore for a leftist perspective. The constant gaslighting against socialism in Zubok's book ("Gorbachev was a Lenin fanboy who only failed because he was still too committed to Lenin") is only tolerable because he's an equal opportunity hater. He hates Lenin, Stalin, Khruschev, Brezhnev, Gorbachev and Yeltsin.

He's part of that type of Cold War-era Russian dissident writers like Solzhenitsyn that got outflanked in their dislike of the USSR by the subsequent course of events following the collapse, where they realized they had a basic bottom line which was that (1) Russia should at least be afforded a degree of national dignity and that (2) the Russian people were still human beings. Solzhenitsyn's Gulag Archipelago still gets endless reprints, which all conveniently ignore how the West's Cold War Soviet dissident darling was sidelined following his post-Soviet collapse Great Russian nationalism and opposition to the partition (he became basically a Republican Party ideologue except for Russia).

This is to say that these types of liberal Soviet writers are unwilling to either (a) be like those Western academics who treat all the immiseration and exploitation brought by the Soviet collapse gleefully as a means to an end and treat the entire Soviet historical experience and achievement as worthless or (b) like those complete ethnic Soviet quislings that blame their people for being subhumans who failed capitalism and liberal democracy rather than vice versa, flagellating themselves for being too culturally stunted to appreciate the generosity of the selfless West.

As for Zubok, you can taste the sheer bitterness in his voice in his epilogue, comparing Western treatment of Russia versus China:

The human mind cannot envision long-term changes. Who could imagine in 1991 that China, ruled by the Communist Party and virtually isolated after the violent crackdown on Tiananmen Square, would become the second and potentially first economic power in the world? And yet, instead of billions of investments into the post-Soviet space and more jobs for Americans, as President Bush had proposed in his Russia package of 1992, hundreds of billions went into China, and many American workers lost their jobs. A quarter of a century later, Graham Allison, co-author of the Grand Bargain to rescue Gorbachev in 1991, began writing about a global pivot of power in favor of China and an “inevitable” Sino-American contest. Even the Washington Consensus had to be modified, to acknowledge the undeniable success of the Chinese economy

[...] Western money went to Eastern Europe instead; and very soon huge amounts of money also started pouring into communist China, which was reopened for business by Deng Xiaoping in 1992. The Washington Consensus and global money markets left not only Russia in the lurch, but Ukraine and other former Soviet republics as well, with the exception of the three Baltic states. Russia and Ukraine competed in counting on Western generosity, support of “democracy,” and geopolitical far-sightedness. Instead, they were left to compete for greedy investors—a zero-sum game that both countries lost. Global financial structures made a mockery of national sovereignty and pride. The elites and peoples of the former superpower suddenly found themselves near the bottom of the world’s food chain

Obviously, any leftist analysis would be able to determine why China, whose market potential had been coveted since the Opium Wars, written about extensively by Marx, would receive this treatment by Western capital when strategically opened up by the CPC compared to the USSR's complete capitulation, which shows the ideological tunnel vision and insufficiency of the liberal mode of analysis. However, his narrative also showcases the complete betrayal of Russia (though Zubok, also a Putin hater to round it off, is too institutionally and ideologically committed to Western patronage and liberalism - perhaps also a lack of courage - to take it to the logical conclusion of why Russia has now re-oriented itself against the West) by the West following the former's voluntary disintegration, which generic Western narratives are loath to admit. His recent "World of the Cold War" book is more bog standard liberal narrative fare however.

For his "Collapse" book, just be aware of the copy-paste of auto-biographical apologia from the main political culprits (Western and Soviet/Russian) which Zubok incorporates extensively in his narrative.