hetzner is currently replacing motherboards of their dedicated servers [1] But I dont know if thats the same issue that was mentioned in the article.

[1] https://status.hetzner.com/incident/7fae9cca-b38c-4154-8a27-...

Thats the same issue, yes.

does pi-hole actually block youtube ads ? last time I tried it did not really work (on pc and phone). Switched back to UBO

They probably do some tricks that blocking ads with DNS is not possible.