It doesn't work well either. If the cursor is already selecting a span of text it can be hard to return it to a single movable cursor and the two finger drag on spacebar thing will just move around the multiselection in a broken way. There is probably some other secret shortcut to toggle, tapping in the text or double tapping just seems to do things at random and rarely gives back a single cursor.

Yep, for all the pride they take in the "it just works" and their "simpler" UI, they certainly love to hide useful features and just not tell you about them upfront.

Yeah, you can read and play around with the phone to learn but something simple like cursor and text adjustment should be priority no. 1 in terms of alerting the user that a function actually exists.