Other than the bullshit computerised systems behind the scenes that are the bane of creators on the platform… it’s hard to think of a more reliable website than YouTube…
I’ve heard Google employees/engineers make jokes (not entirely sure how much is a joke and how much is real) about how YouTube might be the first website back online after WW3 assuming it didn’t destroy the internet (seeing as the internet originally was designed to survive such a thing it’s not entirely far fetched to imagine global chaos and heavily degraded services but still operating in some capacity)