High is good for Affin.
Affin cashback use statement balance.

You can apply BT for affin duo to reduce amount of spending.

Eg 10000 limit for duo

use 7500 for BT 12m 0% , 625 per month

So you need
1000 e-wallet
667 online
758 other spending    --> your balance 2500 credit limit is used here

(+) 625 BT = statement balance of 3050 , to get 50 CB per month

Have u factored in the diff of returns of fd with say ASM, n cost of SST?
Let say diff is 2%, x rm10k, rm200.
SSTx2 rm50.
Total rm250, or rm21/month, half of rm42 cb gone.

have not encountered cc pledged with fd
but i think it's associated with the credit limit available
so perhaps request for lower credit limit?
could utilise the new-to-bank promotion, cash-on-call

it is strange though that they asked u to pledge FD in Affin Islamic for Duo+
i know there are Duo & Duo-i, but don't know if there is a Duo+-i
i m sorry, y do u need duo+ then?
maximising RM 50 cash back is not essential, RM 30 should do fine
however, BT/cash-on-call would be helpful to hit the statement balance
BT is deferring/prepaying/consolidating the payment of other credit cards amount, so u just focus on one account
BUT make sure that u r comfortable with the instalment amount
y do u need to get 2 credit cards in short period?

if primarily 1k+ is more on Groceries, can try Maybank Ikhwan Mastercard (5% capped RM50 per month, Fridays & Saturdays only). worth more than Duo+'s 3% contactless only.

if clinic spend is low/sporadic spend, then skip duo+ and use GXBank debit card 1% cb (no cap) instead. easier to manage.

They probably going to call you again on Monday.
Happened to me not long ago. They called me the following week.

yes, you can do your ewallet topup using Affin Duo+.

are you expecting to get cashback?