By “landing burn” do you mean like an F9 booster where it is essentially vertical and over the target area and then the engines ignite just to null out the velocity?I am slightly modifying this bet rerun. The upcoming expected SpaceX test where Starship reaches orbit velocity and then does a 3/4 orbit around the earth and splash down will count IF Starship actually survives intact enough to do a landing burn. ie. this bet is for a successful orbit velocity and re-entry (but not necessarily landing since it is expected to do an initial "landing" in the water).
I give a near zero probability of that happening on the upcoming Starship mission. While I firmly believe that by the end of this year SpaceX will land a Starship intact and on target after reaching orbital velocity I very much doubt that will happen on the first try.
I hope I’m wrong!
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EDIT: Apologies, now I see the bet is about when a landing — as defined in your post — will be successful, not if the first test flight landing will be successful.