Hello UA experts

I'm sure these questions have already been answered but search is not revealing the right threads!

As a Star Alliance *G member (*G on TG and also PPS on SQ), am I able to book seats in UA's economy + cabin on domestic flights? Also, can I access the domestic UA RCC lounges?

I did both when I flew domestically in the US around 18 months ago, but not sure if the provisions have changed.

Thanks,

B747-438