The article said that. I don't think so Takht will want to clash with any film with it's concept.
I still believe Nadiadwala meant by X-Mas 2021 they'll start filming for Kick 2. If they have to make it ready for X-Mas 2021 then they'll have to start filming now as he'll get busy with KEKD from November. That means no other movie in between Radhe & KEKD.
Anyways everything will be clear once Bigg Boss & Radhe shooting ends completely.