none because they all have limited inventory. More than ever, if one wants PE/J/F, it’s best to pay cash.

I work for a company that pays economy only, so I was always looking to buy international economy and upgrade with miles (complimentary upgrades for status being practically nonexistent). And I will generally not waitlist. My experience leading up to COVID was that years ago AF had lots of upgrade space with FB miles. Then that disappeared. UA had lots of upgrade space for miles, then around 2018 and 2019 that became almost nonexistent. BA had more TATL upgrade space and I was generally using that up to March 2020. (And I like BA more than UA anyway due to lounges and F&B.) Since I have started looking at international routes beginning again in the fall, it looks like almost all of them have more upgrade space (and more discount business class, where it can make more sense just to buy up) Basically, I suggest learning how mileage upgrades work on all of the airlines you are likely to fly, and how to search for it efficiently on websites and using search tools like Expertflyer. Sometimes you have to work hard, be persistent (it can appear, then disappear) and be creative in routing to find an upgrade on an international flight.