I am trying to book this LATAM flight and supposedly you can use Avios to do so. Ive tried via BA site and Iberia plus. Any other thoughts?

MIA to Fortaleza on 10/28/24 at 1125 pm returning 11/3/24 at 435pm from FOR to MIA (stops in Rio I believe)

I see it on LATAM site but can't book it anywhere else.