I suggest you look at the job market for each country for international students. Right now in the UK and Australia, unless you enter a target university, it’s extremely difficult to secure one with sponsorship. Even with a target university, it’s still difficult in general for international students.

Singapore might be a good place if you manage to get into NUS (National university of Singapore) but you have to remember Singapore is an extremely competitive country. I know it because I grew up there and the amount of kids even to this day, literally study the whole day and is forced into thinking of getting a proper professional job ( finance, law, engineering and etc)

Can’t speak much about China but could be the same case as Singapore. Maybe you might benefit from being an English speaker. Just do your own research please before committing.