The way I've come to think about this is that the relevance of the ad to you (as a YouTube viewer), is irrelevant. It matters not whether they are relevant to the content/topic of the video, or whether they are of the kind that SponsorBlock blocks, or those shown by YT algos. The ads serve one purpose, and one purpose alone - to bolster revenue for Google. What may have started out as a 'well-intentioned' (using the term loosely) means to recreate Costco-like ads for the digital realm in the early days of the web, was quickly consumed, like most everything else, by Corporate greed and morphed into a source of user frustration over time.