1. the antenna amp you got (6906074) WILL work with a 433mhz key.
But to change to this amp, it requires a power wire, a ground, and a signal wire to be added as your car with IR does not have the wiring for it. It means running additional wires from the C pillar to the fuse box and body (GM) module.
2. Your car has already has the ring antenna at the key barrel to charge the a diamond key.
But you require a key that is rechargeable. Not all copies are rechargeable, but some are - you must search carefully for the correct one.
You then need to either pair the new transponder keys to the car OR you can remove the chips from your IR keys and put them in the new RF keys, that way you won’t need to reprogram the EWS (security) module.
The RF learn procedure requires no special equipment etc, it’s just a sequence procedure..
I have done this mod myself and got 2 new recharable keys, a new antenna amp, and keys cut for less than $200. - I did the wiring etc myself and I have a ak90 key programmer.
You can have both IR and RF systems working together. Ie 1x IR key as a spare and a RF key as your main key.
Any questions please ask.