Array.isArray problem with narrowed type

Hi, I recently saw your YT video and wanted to add ts-reset to our project. But there is an issue which I find difficult to overcome:

Basically the problem is that isArray is always adding the type unknown[] to my variable, which I know is of type T | T[]. So when I check whether it's an array, I should know it's T[], but TS now thinks it's T[] & unknown[] which is a problem.

I tried to replicate it here: https://www.typescriptlang.org/play?ts=4.9.5#code/JYOwLgpgTgZghgYwgAgIJSnAngYQPYgDOYUArgmHlMgN4BQyywh6mWAFHFAOYBcycEFgCU-LtyaFkpEAGsQeAO4gA2gF0A3HQC+dOmCwAHFAFUQXNgB4AKgD5kAXmTXkEAB6QQAEymtsl0BhoZBN7AH4Q5H5rLToYGQpgAmRIYhtbdgA3OAAbUgho4Vo6AEhShAJiJhAQYKdLAA1XDwhvKTMLfzsMzP4G9SKHe3oSkoB6MeRS3TKS4Bhkdj8sADpmZazc-OEikbma6E28iGEtEt1tIA

Any advice maybe? :)