It is sometimes tricky for me to disable adblocking! There are a couple of approaches. Resetting my DNS servers to defaults is disruptive and error-prone; it's a non-starter. I find it peculiar that there is no knob on NextDNS that says "disable blocking features and act like normal DNS" even though they themselves enable such a feature if you run out of free monthly queries. You can disable a bunch of features one-by-one, but of course that affects all sites, not just the one. You can whitelist any domain you want, but that involves a cycle of testing and guessing which ones are emanating from the site you want to use.
In short, there's no straightforward way of just telling NextDNS "don't block ads while I'm on YouTube.com" and it's for that reason that I sort of miss uBlock Origin. However, YouTube does use native domains for all its ad serving, and I see them all now anyway, so I don't believe that this new policy will adversely affect my usage profile.