Should I use OCBC 360 or DBS multiplier?

I’m a young working adult w/ a take home salary of $2240 and bank balance of $30,000. My monthly expenditure is approximately $500-800 including insurance from GE. Will OCBC be better for me since I’ll very likely hit $35,000 soon and thus enjoy the better interest rates? Also, which credit cards will be appropriate for me? Leaning towards OCBC as there is the GE cash flow card to help me do monthly instalments. Please advise!