I tried speaking to support to find out if I could downgrade, some of my colleagues don't have this feature. They couldn't(/wouldn't) tell me how to.

One thing that isn't mentioned is the behaviour with pressing up to edit a previous comment, it will put you into the span if the span goes to the end of the message.

I've also had numerous times where the span hasn't closed correctly leading to things in backticks not being formatted correctly (I'm guessing timing issue due to their move to react for this stuff).

It's incredibly annoying. If I didn't have to use slack for work I'd probably bin it.