I have also noticed that many flights will show no inventory to partners, but if you're booking with AA miles you might find a web special award (available only to AA members). Often those are just a few thousand miles more than a standard OW/partner award. It seems they are prioritizing their own program which I guess makes sense. With international carriers operating significantly fewer flights right now I'm not surprised they're flying more full and are therefore releasing less inventory than 2019 or early 2020.