For me:

1) don't do airline credit cards. Put necessary spend on other credit cards with better return.

2) partner earning but only PE and above generally make sense. Inexpensive economy fares usually have limitations on PQP earning (e.g. less than 100%).

2a) don't have any reluctance with non-UA ticket. If I am buying a ticket, I am flying the ticket, short of some unforseen events

Being flexible is the key.

Also not UA focused (free agent), so a good deal is not limited to UA/*A only.