If I am an existing gTLD registry operator and I apply for allocatable variants of my existing TLD in the New gTLD Program: 2026 Round and am approved, will I need to transition to the 2026 Base RA?

Yes. If an existing registry operator applies for allocatable variant strings of an existing gTLD in the New gTLD Program: 2026 Round and is approved, the registry operator must transition to the 2026 Base RA.