Trying to balance one side of earbuds balances both sides together

I'm using Galaxy Buds Plus with an external Bluetooth adapter.

My right earbud sounds low relative to the left one, on my computer and on my phone.

I managed to balance them on my phone, and everything was okay. But I can't balance them through Windows for some reason. Every time I try to balance one side, it balances the other one immediately.

Any thoughts? Much appreciated.