My instinct is that you'll be happier going back to Singapore if possible, if you can afford it. It feels bad to be held back from your ambitions and stuck in a depressing place.

21 days of quarantine might seem like a lot, but you're already spending months and months trapped in a place you don't like. Is that any better?

However I know it's a more complicated decision than that. I hope you find some clarity, either way.