There are cards that offer up to 2% cash back equivalent e.g. Alliance Platinum for max RM5K/month where you will earn max RM68.75 cash back and 5K reward points.
So if you can split the expenses into 2 different statement cycle, you will earn RM137.50 cash back and 10,000 points.
But if you consider GST, you'll only earn RM87.50 cash back and the 10,000 points can use for next year GST.
And if you currently have a card like HLB Essential which earns you 1% cash back, you'll only be earning extra RM37.50 (RM137.50-RM100) not including the points.
So if you ask me, why go thru all the trouble just to earn less than RM100.
If you consistently going to spend RM5K/month , the Alliance Plat is good.
If they going to be imposed surcharge, better you pay with cash. If you really think about it, the 3% surcharge is like upfront interest where you have to settle within a month or so, therefore, the "effective rate" is like more than double.
My advise is go survey more and ask if the shop got 0% installment scheme. If you buy some stuff at Ikea or Courts, no surcharge for CC and can use AMEX

These are the 4 (or 5) cards that I keep.
A) CIMB Petronas Gold MC- my first card and tied to installment for Diamond water filter.
B) Standard Charted Gold Visa - keep this card as GST waived.
D) OCBC Titanium MC.