As a Malaysian who has lived and worked In Singapore for many years I would say its not hard to integrate if you blend in. Singaporeans respect performance and ability. But it is a very materialistic society, not racist but people do respect money. Some look down on Malaysians and foreigners whom they think go there because they are financially desperate, or may resent those taking their jobs. But most will respect those who do well.
I would say though that 3.5K salary for a 30 year old isn't high considering the high cost of living. So you need to think whether it is worth it. For me it would be too low. You will have to lead a really simple life.

You are young enough to give this a try but not for too long. Why not try it out for 2 years? Singapore is a land of opportunity. It is just that the lifestyle and cost of living are quite different. I moved there in my teens, adapted easily. My friends and relatives who went there to work as adults, especially after 25, didn't find it as easy to adapt. I would try to get an offer with higher pay or nego for that if I were you. Will you be on Employment Pass or S pass?

All the best whatever you decide. I am.sure you have heard the work culture there is quite different. Not much of work life balance. So long as you are mentally prepared.

Give it a go since you have this opportunity. Worst scenario, if you don't like it just come back

You are right. Anyway you can only buy hdb if you are a citizen or PR. PRs can't buy brand new, can only buy Resale unless married to a citizen and buying together.

Good for retirees