This doesn't sound like a 3 star review.
You can try to use an incognito window (extension can be enabled there too) or logout, or use another browser (or another computer.)

The topic of youtube experiments is pinned in our repo:
https://github.com/code-charity/youtube/issues/4143

(you received an update from us days ago too, it should have improved a lot while avoiding any disadvantages, yet it could also be responsible for a specific features change that you noticed.)
thanks