You're on landed? I got mine a while ago. P.perdana area. But now my line has been down for 2 days lol

For the LAN, that's probably the max even with new router. At times maybe your speed test can show 48-48. But for wifi, try to improve your home wifi design by analyzing first how to improve link speeds around the house before jumping straight onto a new wifi router without analyzing actual needs in the first place.

This is because sometimes, newly purchased router actually performs just slightly better than stock which doesn't justify then new purchase. If you opt for things like powerline then use wifi ap, then maybe you'll actually be improving the network quality on average as linkspeed can be improved.

Is your router set to 40Mhz? Apple devices will only use 20Mhz channel width at 2.4Ghz so maybe that's why. But even then it should be able to reach 80-90 mbps in good wifi conditions. Laptop & Xiaomi probably using 40Mhz.