Yes. There is a huge difference here for bigger flat.
With Ethernet Backhaul, you can use cheaper dual band mesh solution. The placement of the mesh nodes are also flexible.
With wireless backaul, you may have to use triband mesh solution. The placement of the mesh nodes are also more difficult, typically with line of sight or with only one wall in between.
You may want to update your floor plan with the locations of the LAN ports available.
Without the info, I think one potential option for you may be M1 6Gbps offer with dual ZenWiFi BT10 top-up. Two ZenWiFi BT10 will not be able to cover the flat either, maybe aother two units, total 4 nodes.
M1 6Gbps plan offer --> S$34 per month, top up at S$12 per month, total effective price is at S$46 per month. Then M1 has PWP (purchase with purchase) offer for S$21 x 24 month = S$504, for another two units of Asus ZenWiFi BT10.
https://shop.m1.com.sg/fbb/plans-bundles/fbb-plan?plan=HOMEPAC_6GBPS_24
But better to use a more powerful main router for a 4 nodes system, since Asus ZenWiFi BT10 has a weak CPU, say Asus ROG GT-BE98 as main router, plus three Asus ZenWiFi BT10 nodes.