Enoch Inri for Victoria 2, Dino Stan for CK2, Breadgod Gaming for CK3, ISorrowProductions for HOI4. The majority of CK3 Youtubers are blatant paid shills, they can be entertaining but I'm confident Paradox glazes them to praise the game in return for liaisons with the company and giving them exclusive info on upcoming updates, generating both hype for Paradox and high views for the Youtuber. They even invite some to their studio, which is then typically followed by an uptick in videos from said YouTuber.