IMO, after reading all the comments, suggestions and TS's posts about his wifi speed at 300Mbps, double storey house and still under construction, my opinion is to get every room with Ethernet Cable Dedicated directly from your main router. After that, get a decent router up to your allocated budget for your router, personally i will go for Asus. Been using Asus for years. Just got a refurbished AX88U for my room because i have a few devices I want to link up to LAN, 2 PCs, 1 NAS, 1 PS4 and in the future some additional electronics like TV with LAN support, hence why i went with Asus AX88U. It comes with 8 LAN slot and 1 WAN slot. Currently my house have free upgrade from 500Mbps to 800Mbps. I also have another AX56U for my work PC and that will connect to a printer. My room will have a printer also and I plan to connect it to the AX88U too.. lol. Basically better get 2 routers, same model also can, and run a LAN cable up to the first floor router. I have 1 main downstairs, AC86U, upstairs now 2, which is overkill I admit, AX56U and AX88U. Both serving different PCs. See which is your budget, AX56U is more than enough if you have not many people in the house. My house is cause my parents have a few devices each... LOL. so yeah, hence why i upgraded the routers. I just flashed my AX88U to default firmware, it was Merlin firmware. xD

My first Asus router was the N56U i think. And i bought it 2nd hand too.. Lol. That time it was like RM100, way better than the default TM router, useless like anything. My mom keep nagging me saying the wifi so slow. lol. Ended up with that router for i think 2 years before it KO-ed. Bought another 2nd hand N56U. used for a year and it seems like it was gonna KO, so i bought AC86u that time, bought wrong time, because right after that price dropped drastically.. lol. Bought at RM800, i think a month later was like RM600.. I bought same time with my AX56U, just launched that time, RM600 AX56U. lols. Oh wells. haha. What's done is done. But I am very satisfied with Asus routers. The UI is very easy to navigate. Overall I would recommend Asus. xD

haha.. or wait for sale.. xD