Anything that tempts people to pride, that would tempt them to think of themselves as gods, ought to be opposed.
If, somehow, in some non-trivial non-sophistic way, a way filled with true humility, transhumanism would lead people to God and help them acknowledge His greater glory, then perhaps it would be embraced. I have to say that I don’t know what that would be though.
Honestly, I think the former (pride) seems much more likely to occur than the latter (acknowledgement of God’s glory and mercy).
The church would probably say at this time that the best way of getting to God has already been provided: prayer and sacraments.
Finally, if an attempt at transhumanism led to botched experiments filled with needless suffering, I think that would probably end up being rejected by the church too.
Admirable is the name of God.