2012 Rough Idle under load

Hello fine people of Reddit. I recently got a new to me Pro4x Xterra and have been battling a rough idle since I got it. I got a few engine codes such as P0133 and P0171. All of which have been resolved with a new upstream O2 sensor and cleaning the throttle body and maf sensor. I changed the air filter even though the old one wasn’t very dirty. The rough idle still hasn’t gone away even though I have no engine codes. My next steps are to replace the PCV valve as that likely hasn’t been replaced in this trucks lifetime. After that I’ll pull a spark plug and see if they‘ve ever been replaced. I guess I’m hoping for some confirmation that I’m on the right track or if there is some Xterra quirk I don’t know of. Thank you.