Currently have $50 in stashaway only. Not dca-ing into stashaway now. Dca-ing 400 into etfs (200 into Nikko AM ETF and 200 into ABM ETF). Should I change the proportion and invest more into robo?

I think Nikko AM STI ETF is one of the best ways to get invested in the Singapore equity market. Given its expense ratio of ~0.28%, it should not be considered expensive. The only thing you should check if when you buy for 200$ each time (say monthly) how much brokerage do you land up paying. So if you are charged 5$ to buy 200$ of an ETF then it would be considered very expensive.

W.r.t ABM I would suggest evaluate a balanced Kristal like All Weather / All Rounder / Steady Growth based on your risk profile or just take any balanced portfolio of US Equities (SPY), EM Equities (VWO/EEM) and Gold (GLD) clubbed with Bond ETFs (try UCITS preferably LQDA or a BND, LQD)

Also, do run the algorithm at kristal.AI (investments up to $50,000 are free) and see what that shows for your profile. Happy to help out if you need more info.

Investing more into robo would be a great way to diversify your portfolio and gain exposure into the US market