There is any Pose-T for the UE5 Mannequin?

I understand! Though it may take your 30 minutes to an hour now, but you could in theory reuse that asset throughout your projects. I had done the same thing back in UE4. Had a manny skeleton set up and ready to immediately retarget to mixamo imports. The workflow is a bit different now, but it might save you some time in the long run!