I've had success with just dish soap - it makes blockages "slide" more easily.
In the last flatshare I lived, I had a particularly annoying combination of a slow toilet and a flatmate incapable of solving any blockages. Whenever I'd see that, I'd go "fuck this", squirt a silly amount of Fairy in the bowl (I'm talking like 100 ml at least) and usually the blockage would resolve itself overnight.
Even assuming we're okay with using AI for language learning - then why would anyone pay for Duolingo instead of the many LLMs that people already use and pay for?
They've alienated their customer base hard. And this marketing video pretending they are siding with the users and against "their corporate overlords" is horribly tone deaf.