According to that page, BAE systems et al were using kevlar soaked in a solution of polyethylene glycol and silica nanoparticles.

All readily available online, if you can afford something like $200 per 2ml of silica nanoparticles. It would be amazing to see one of the YouTube channels that has tried making their own, just make the real thing.

I imagine a suit made of dripping wet Kevlar wouldn't be too comfortable though. John Wick would experience some chafing.