u may need to check with maybnk for any penalty fee for early settlement

Yes, you don't even have to wait a few months. I assume your scenario is as follows:

Bank A RM10k transferred to Bank B (now Bank A has 0, Bank B has 12 months instalment of RM10k)

Bank B's outstanding balance (e.g. including any BT instalment already charged to the card) can be freely transferred to Bank C at any time, subject to Bank C's terms and conditions. For example, Bank C may require Bank B's latest statement.

In short, your BT applications with different banks are mutually exclusive. You can even do simultaneous BT applications with Banks A, B and C (all to each other haha), as long as you meet each individual bank's conditions (typically you need sufficient credit limit, and possibly a copy of the latest statement of the bank you're transferring from).

No need new card to get the 0% promo