I think this is where the disagreement on rules interpretation is focused.But remember the current rule.
They have to maintain possession all the way through landing on the ground.
The "must maintain possession all the way through" applies only when the player is going to the ground while in the process of making the catch.
In this case, the receiver was upright when the process started, and only started going to the ground after being tackled by the defender.
The only "football move" possible was being tackled, or if you want to be a rules nazi, "going down and taking a knee".
If he maintained possession and control at any point while his knee was down, that was a catch and down by contact.
My eyes tell me that between the time his knee was down with his back facing upward and the time the tackler had flipped his body 180 degrees and his back was facing downward, the receiver had possession and control for a measurable period of time.
That would make it a catch and down by contact per applicable NFL Rule 3, Article 7.
Also, Rule 8, Article 3 states "movement of the ball does not automatically result in loss of control". My eyes tell me he had control of the ball by his hand keeping it pressed to his body during the time he was face down with his knee touching to the time he was face-up on his back.