Oh no, please.

Will uBlock still work or will that also break when/if this gets added?

As I understood the ad will be a part of the actual video file you receive but, unlike fixed sponsor integrations, the time it’s shown at will change every time. That is going to be impossible to fix unless there are some exploits

They will also want to block people from skipping the ad. So they’ll have to provide timestamps, when skipping should be blocked. Maybe those can be somehow extracted.

That’s a pretty good idea. As soon as skipping is disabled, start skipping. And stop skipping when you’re allowed to skip again.