Just to confirm before I go all charging-at-jet engines like a modern Don Quixote...

There's no way to waitlist PlusPoints on a reservation that has not been ticketed, correct? (I can think of at least 5 reasons why this would/could break things, but can't resist asking )

My wife has a government TA booked (but as far as I can tell not yet ticketed) reservation in a few weeks... I'd love to try to surprise her and I know the PPs I currently have are unlikely to be useful before expiry based on what's already booked up front and travel that's unlikely to occur based on geopolitical stuff. I can pull the UA PNR on the app but the upgrade button doesn't appear; .COM throws "lost in space" error and won't even display the reservation. A friendly UA agent has confirmed that they can see the reservation and that all segments are HK1 but it doesn't appear to be ticketed. Reservation was booked ~2 months ago and she is able to assign seats and all of the other niceties.

IIRC from past travel the TA/TMC doesn't actually ticket any travel until very close to departure so that doesn't surprise me.