How can I delete sub-account B?

I purchased Path of Exile 2 - Path of Exile 2 Early Access Supporter Pack on Xbox and have linked my Xbox account on the POE website. I can currently play POE2 normally on Xbox.

Now, I want to play POE2 on PC, so I linked my Steam account. I noticed that I have two sub-accounts on my account: one sub-account A, which I often use to play on Xbox, has 300 points, and the other sub-account B, which I used to experience POE1 on Steam, has 0 points. I'm a bit confused.

If I purchase Path of Exile 2 - Path of Exile 2 Early Access Supporter Pack on Steam, will the new 300 points be available for me to choose to add to sub-account A or sub-account B when I enter the game? Or will they be automatically added to sub-account B with 0 points without my choice?

I'm currently very confused. I just want to continue playing on sub-account A, and I want the points to be used on sub-account A as well (since I've created characters and bought some storage there). If the 300 points purchased on Steam can't be added to sub-account A, then my purchase on Steam would be meaningless. Because of this concern, I haven't dared to make the purchase on Steam yet.

I would like to ask if anyone can request GGG to delete my sub-account B? Or is it possible for me to transfer points from sub-account B to sub-account A myself? I contacted customer service a few days ago, but I haven't received any response. I'm worried that they might not have seen my email due to the high volume of inquiries.