Hold the home button and then ask Google, or say "hey Google, that's on my screen?".
It's a bit of a pain in the arse... Usually it says "sorry, I can't read that" and I have to tap "read my screen" and"what's on my screen?" A couple of times, but eventually it does it.
It can't read everything though, as you know if you've used it before.
This worked, thanks! As you said though, doesn't seem to read much. Seems like its even worse than my previous Android 9 device.