I can’t find an earlier source. And it’s not accurate:

Boris Johnson Pressured Zelenskyy to Ditch Peace Talks With Russia: Ukrainian Paper

In the weeks ahead of Johnson’s April 9 visit, high-level diplomatic talks held in Belarus and Turkey had failed to yield a diplomatic breakthrough, though reports in mid-March indicated that Russian and Ukrainian delegations “made significant progress” toward a 15-point peace deal that would involve Ukraine renouncing its NATO ambitions in exchange for the withdrawal of Moscow’s troops.