It's a PITA to convert a Bind Pose from A to T for CC3+ characters. But it's possible with some effort.
You need to make two trips from CC > Blender.
Check a few of my posts from here if makes sense:
https://forum.reallusion.com/FindPost480091.aspxThere is more to it like saving character cloth /skin and reapplying before the final export from CC.
Let me know if you have questions.