What minimal size would a lump sum need to be in order to generate a stable passive income, and which investment venues/choices would be the best for it?

Will have to know your age! If you're younger, most would look for capital gains from the US market, be it stocks/ etfs (I'd recommend Ireland-domiciled etfs).

My personal strategy would be to look for capital gains first, and then when I'm older, divest and diversify more into income/dividend yielding stable companies. As 5% dividend yearly for maybe 200k is only 10k a year. Therefore I feel its better to look for capital gains earlier in life as we can stomach the volatility and we have time to compound!

Hi! I personally would prefer dividend investing.

It depends on how much your are expecting in return! Note that dividends can fluctuate and can be quite cyclical. To have sustainable passive income, aiming a 3-4% dividend yield is fairly reasonable. If we are aiming for 3K per month, we need 36K a year. That requires us to have a 3.6% yield on a 1 Million dollars portfolio.

Not many have spare 1 Million lying around to get there. I don't, but I personally have similar financial goals to get to a point to have a sustainable passive income.

For dividends, Singapore is much better, we do not have to pay 30% tax like on US stocks. The companies, in general, in Singapore are more directed towards more stability, defensiveness and dividend payouts.

However, to reach that amount of money it will be very slow investing in the Singapore market. China and US provide much higher capital gains