I regularly use CC connected by wifi (aka wireless device driver) myself. However, I did already have my android phone (Samsung Galaxy S10e) configured in RL. (I use RL to
delete new books from CC now due to
the problem described here. I doubt that makes any difference to this.)
I also see the 'Add Device' button in RL disabled, but I assumed that's because it's already added... I agree that RL's config is not showing my phone as 'Connected' like it does my Kindle Voyage.
Given your report, I hesitate to remove the device entry for my phone and try to re-add it.

I'll try to dig out another phone to test it with.