According to, of all places, an independent citizen media named the Dorset Eye:

[https://dorseteye.com/boris-johnson-admits-that-the-ukrainian-far-right-destroyed-peace-deal-in-2019-not-putin/]

Boris Johnson Admits That The Ukrainian Far Right Destroyed Peace Deal In 2019, Not Putin.

...

Despite narratives that paint Putin as the central figure in obstructing peace, the 2019 efforts demonstrated that Ukraine was not merely a victim of Kremlin interference. While the Russian government continued to push for the implementation of the Minsk Agreements under terms favourable to Moscow, it was internal nationalist resistance that played a decisive role in preventing a diplomatic resolution.

Dorset Eye goes on to say:

The role of Ukrainian nationalists in blocking these peace efforts challenges the oversimplified narrative that all nationalist elements within Ukraine were purely defensive in nature. Instead, their involvement in 2019 highlights a political landscape in which nationalists, while staunchly protective of Ukrainian sovereignty, also played a key role in derailing potential diplomatic solutions.

There is also the argument that this just Boris undertaking some 'reputation management' as he is usually credited/discredited with undermining the 2019 peace talks.