I’m in my 20s, still studying, are there any value-adding part-time jobs in the banking sector? I've already started investing on STI ETF, and I'm looking into robo-advisors next. Should I enter in lump-sum or DCA? How should I take my next step?

I’m in my 20s, still studying. Particularly Economics and Finance from a private university. Already started on STI ETF through RSP, looking into robo advisory next. However, should one enter robo advisory in lump sum or DCA? Also, where are some good places to look for value-added part-time jobs such as in the banking sector? I have school on every Monday and Tuesday, will I be able to find one? Or even where to find internships during my holidays? Lastly, i hope there’s someone who could mentor me or someone who are interested in investment that can impart some knowledge.