Just wondering why you want to change?
I assue you are using ONT, if you read the first post, it is okay to stay with Singtel for ONT users. If you are not happy with Singtel issued router, just get your own router. For example, Asus TUF-AX4200 (at around S$249) can be a good choice. If you have low budget, then TP-Link Archer AX72 (at around S$80) is also not bad.
Singtel is quite stable for ONT users if you use your own router. Arguable it is the most stable consumer ISPs out there but with certain drawbacks like international latency. But I guess you are not hit by the issues mentioned in the second post of the thread, right?
But if you want to move out of Singtel, then yes M1 is a good choice.
1. Depends on the server. Latency is more important. In terms of latency, Singtel will win for China. M1 will win for many international locations. Speed does not really matter much in reality but Singtel will win a bit in general.
2. Please refer to the answer here. For M1 users, I will recommend to top-up for Asus GT-AX6000.
https://forums.hardwarezone.com.sg/threads/which-router-is-better-asus-or-tp-link.6952537/
3. Please read the first post of this thread. It is said that you will be okay if you add Static IP and not using Freedom DNS. VQ is good in terms of speed and latency for many locations. Latency to China is not good as per the reports.