should be ok altho to be fair i have never done it, and i would not necessarily recommend u do it on the same day..

what i would normally suggest is you transfer 3k in near your credit card due date, pay the statement, then transfer out the remaining amount

But you credit card credit limit will be updated once the payment has made from your PSA account? 

I believe so.
If I remember correctly, even you pay using Instant Fund Transfer/DuitNow from other bank, the online ledger isn't updated immediately right?
But your credit limit will be reflected after payment made.

you can do so. fresh fund of 3000 one time transfer in, then transfer out for spending. You do not need to hold the 3000 throughout the month.

of course the more balance you have daily, the higher interest.

Actually I did not tweak any setting at all.
Okay I enabled the card-not-present.

Guess I need to call the customer service to ask what's wrong.
Under help & services in SCB mobile apps, got a section for debit card activation. But the card is not shown when I enter the section. (My debit card is shown in other sections.)
So debit card also required activation just like credit card?
Is not new card. Already got it for more than 1 year. But didnt use before.

to get the 2% quarterly bonus for having incremental average balance of RM3k each month, your account must show an average 3k increase every month for 3 months in the defined quarter (Feb-Apr, etc). If you miss one, you get nothing. to get the full year's worth, you will soon realize you need to dump in an additional RM36k, and can't take out any funds as it will reduce your IAB, so that's 2 glaring problems:

1. you need to deposit an additional RM3k every month for 12 months consistently and in the end fork out RM36k to earn that 2%
2. you can't take your money out or you lose the bonus interest, so it's no better than FD

Yes, I'm still getting it. However, in progress of moving the funds away from this account already.