I bentch using a regular Ashkenaz bentcher. In most of them, the word after “Rachem” is Na but it’s in parenthesis. I think I’ve also seen the word omitted occasionally.
I see the Shulchan Aruch 188:4 brings the Nusach as Rachem, without any Yesh Omrim, nor does the Rema comment. Where are sources that say to add the word Na?