If you teach online, which tool in your stack would you drop tomorrow?

Not rhetorical. I am trying to decide what we build next and I would rather ask than guess.

Context so you know my bias: I am building Prolaud, a course platform with the live classroom inside it. We launch here on 6 October.

Why I am asking. We started this because we were running classes with four tools taped together. A video tool for the class, payment links pasted into WhatsApp, a Google Sheet for who had actually paid, a design tool for the certificate at the end. Every month a student's name fell through the gap between two of them.

So if you teach anything online: which tool annoys you most, and what would have to be true for you to stop using it?

If the same answer shows up three times I will build it and come back to this thread to say so.