Were they 1-2 usual normal ads or 5-10 new unskippable ads before starting ever video?
If they were 5-10 ads, you were automatically enrolled into new user study https://www.ghacks.net/2022/09/16/youtube-is-testing-up-to-10-unskippable-ads-before-videos/.
Make sure that ad-blocking is turned to aggressive mode for youtube brave://settings/shields.
Go to brave://components/ and update your filter lists and ad-blocker (it must have auto-updated itself).
Ad-blocking is a cat and mouse game, if ad tech changes anything in their code on how they serve ads, adblocker need to simultaneously change their adblocker code (update filterlists). The official brave team member, fanboyz, will look into it.