Does it seem that the DBS Multiplier is not as competitive compared to the UOB one account due to some conditions?

I would say both have its own strength and weakness. For DBS Multiplier, you can hit actually hit salary crediting, credit card spending and investment category. If you were to do a SSB ladder, you can get the investment category part of the crediting dividends as long as they don't change the criteria. All you need to do is to buy 6 months of SSBs consecutively and make sure your CDP is connected to DBS/POSB account. This way, after the 6 months of buying SSBs, you will receive SSBs interest every month for 10 years which will count as investment category under DBS multiplier. SSB minimum amount is $500 every time so it will take you at least $3,000 but of course, you can put more if you want to. The more transactions you have with DBS, the more interest you get. But for me their credit card doesn't really suit me, they have slightly higher minimum monthly balance, an additional step which is the SSB ladder and I don't have that much transactions in the first place.

For UOB one, their credit card gives cashback for most stuff although you have to spend at least $500. (not very hard if have fixed expenses that UOB one give cashback.) Their EIR or effective interest rate is only 2.44% if you have 75k in the UOB one account. They also allow 3 giro transactions instead of salary credit so a bit different as well which means if you plan to keep a big amount of money with the banks you can do both DBS multiplier and UOB one at the same time with a single salary crediting. The headache part is if you don't hit $500 for a single time, you won't get the interest and you won't get the cashback for the quarter.

Overall, just choose the accounts and credit cards that suit your need the most.