If you plan to give up Singtel TV, then just go with M1 and get the TP-Link Archer AX72 (free with 1Gbps plan or buy at S$80 for 500Mbps plan).
Singtel AC Plus is the worst router from any SIngapre ISPs in the past 10 years. Maybe only Starhub Nokia Beacon 1 came close. So any current router in the market will be better than it.
However, you need to post the floor plan to see if a wireless media bridge idea will work or not. In fact, Archer AX72 will work in EasyMesh mode with Wireless backhaul and Ethernet backhaul, so you can get another unit if the floor plan is suitable.
M1 ONT -- TP-Link Archer AX72 main router -- wireless backhaul -- Archer AX72 EasyMesh node -- PC
Reference on TP-Link EasyMesh
https://www.tp-link.com/sg/support/faq/3529/
https://community.tp-link.com/en/home/forum/topic/593722