TAA just means temporal anti aliasing. Temporal as in relying on data from the previous frames.
The implementation of DLSS and FSR are wholly separate from the old TAA. Yes, they work on the same principals, but do their own thing.
TAA as a setting gets disabled because the newer methodes fully overwrite it. Some games hide the old setting, others gray it out, it depends.
I get all that, but it’s still not what I’m trying to explain. If TAA is forced in a game that supports DLSS/FSR it’s still not used in the image itself, but rather just the motion vector data gets piped into the new algorithm.
Otherwise even with DLSS/FSR active you’d have all the smearing and bad quality of the original TAA implementation, which you simply don’t.
So it’s just pedantic if a toggle in a game appears on/off or at all, if the engine just uses the motion vector data and then uses DLSS/FSR/XeSS or what have you to actually do the anti-aliasing.