I find that, for me, the best thing I can do to get around a block is to stop attacking it. My mind works in the background and eventually produces a strong solution.
Some specifics are: long walks during which I intentionally don't think about that project, a few days writing another section or tackling a different piece entirely, or editing for a while rather than writing. The best thing I can do for a book-length project after the first draft is stop looking at it for a few months, but you can apply the same principle (that taking your conscious mind off the work allows new thoughts to percolate) for any duration during the drafting process.
I agree with Powderhorn's assessment, though, that your framing of this hurdle sounds less about struggling to compose sentences and more about struggling with the content emotionally. In those cases, I tend to lean on friends or writing partners and aim to talk out/about the issue before putting it to paper.
I hope you find a new creative path forward!