First of all, I hope you are well and healthy my friend.
This is a very tough one indeed.
My heart tells me you should keep the PO, but my heart says you should keep the Sub. The Sub is more comfortable, more versatile; the ultimate do it all everyday watch. But, as I said, my heart says you should keep the PO.
You are the first and only owner of the PO and it really is (IMO) the best Omega in decades. After all, when were mechanical watches ever a rational choice? It’s all about the story, history and how they make you feel! In that case: keep the PO and move the Sub.
Keep us posted and good luck!