Why does the router cut speed?

Question

Computer networks

I changed my provider, took a higher speed - 70 megabits, and then it turned out that my router did not quite suit me. On the wire, my provider gives all the declared speed, but through the router the speed is cut. "As is" the router gives out 25-30 megabits on the speedtest. I checked that with the congestion of the channels. I switched the router from channel 1 to 13 and reduced the channel width from 40 to 20 MHz. This gave a small boost. Now the speed is 35-40 megabits. Here is a screenshot by channels:

I have a couple of questions about this:
- Can I do something else with this router, adjust something, change it? The router, by the way, is quite cheap TP-LINK TL-WR720N
- If nothing can be done about this router, the screenshot above suggests such an idea. There is only one network in the 5GHz band in my area. It hangs alone. Does it make sense for me to buy a 5GHz router? Will I be able to extract all the speed given to me by the provider in this way? Advise a good router for these purposes, given that there are 6 devices in the house, of which only 2 support 5GHz (that is, the router needs to work simultaneously in two bands) and one computer is connected via a
UPD cable: I took TP-LINK Archer C50

Answer 1

what type of connection do you have? ipoe or pppoe are less brain-intensive than pptp or l2tp.
what is the budget?

Recommend a good router for this purpose, given that there are 6 devices in the house, only 2 of them support 5GHz

name these devices. to stationary workers (or laptops) that burn torrents, IMHO should only pull the cable. Wi-fi is a common hub, tomorrow a fierce neighbor may appear there, who will finish off the broadcast with crooked devices. For waffles - tablets and mobile phones, they have 10-20 Mbit / s - enough with a hook. If you are completely unbearable, but you want some stability, take powerline adapters to test.

Can I do something else with this router, tweak something, change it? The router, by the way, is quite cheap TP-LINK TL-WR720N

a very good platform for experimenting with openwrt, don't throw it away.
on routers:
mikrotik hap ac lite / hap ac - you shouldn't be afraid, they washed down the web muzzle well. (you won't have to climb into the jungle). On stability for SOHO - pieces of iron are excellent.
well, or in extreme cases - tp-link wdr3600/4300 - because of openwrt support. I did not use new castrated archers with 802.11ac support, but their SoCs do not inspire confidence. (It seems that they also promised to screw up alternative firmware)