>>53822113Landorus-T will fulfill an entirely different niche now that it doesn't have Knock Off or Defog. It has Tera Blast now, meaning it can finally use Flying STAB, meaning Landorus Therian will be more offensive with Tera Flying + EQ + U-turn/Swords Dance while Landorus Donphan will be the hazard remover par excellence.
Lando will definitely not be seeing quite as much usage in Gen 9 unless it gets Knock Off and/or Defog back, though. The reason it was #1 in usage is because it filled so many vital roles on a team. If all it is is a powerful physical attacker without any way to status (Toxic) or any utility (Defog), it'll see significantly less overall usage.