No, not the debit card number.
GXBank also had savings account number. Use the account number to transfer/receive money instead.

You open GXBank app, tap Main account.
Under the total amount you see on top left corner of the screen, you'll see there's something like 8888-00123456-7
That's your GXBank savings account number.

Not "any transaction" on the debit card....

There are a list of exceptions...
As long your transactions don't fall under these categories, then you will be eligible for the 1% unlimited cashback:
https://help.gxbank.my/perks-and-rewards/GX...ing_cashback%3F