WiFi setup. How to set up the router correctly?

Question

WiFi

We have on our hands an
apartment of 3 rooms. 65 sq. brick wall.
100mb/s input.
Microtik RB951Ui-2Hnd
ZyXEL Keenetic 4G II
Xiaomi MI ROUTER 3
Any of these gives at best 30 Mb / s. Constant drops in wifi connection. In the back room, LTE works faster. In short, any of the routers saddens with such jambs. Mikrotik just pissed off so that for 15 minutes the phone a meter away from him could not connect. while the same iPhone works in its network. The TV (YouTube) works stably only via Ethernet. A bunch of zyxel + xiaomi in repeater mode leads to
that the network generally hangs. Tell me how to properly configure the network? I'm just looking for the channel with the fastest connection. But that doesn't always work, does it? Before that, he lived in a private house, where the fucking Rostelecom through adsl worked more stable =(
PS. There is a military unit right in front of the house. Can this affect?

​​5G does not break even one wall

Answer 1

15 minutes the phone a meter away from him could not connect

this is absolutely not how it should be. This means that either your air is jammed tightly, or one of the devices is faulty, but the latter seems to be excluded, since you say that this is the case (or only a little better) - with all devices.
Put https://www.acrylicwifi.com/en/wlan-wifi-wireless-... take a full screenshot of the list of networks, add it to the question, and it will be clear what you should do.
Most likely - either look for a free channel, or switch to the 5GHz band.

Answer 2

There is a military unit right in front of the house. Can it influence?

maybe. Just like a bunch of neighbors with similar points ... plus a cheerful neighbor using cameras with "radio extenders" (really had to pull up people with special equipment ... and as a result, several 700mW transmitters were found in the 2.4 GHz region ... in this scenario, "see" the point was not further than 30 cm, and the connection lasted a second)
as one familiar radio engineer-developer, including wifi pieces of iron, said: "stretch the wires")
an intermediate alternative for problems with laying the cable - powerline to the rooms, and there is already a distribution of 5 GHz and then only to mobile devices, and more or less stationary - better with a wire

Answer 3

Mikrotik just pissed off so that for 15 minutes the phone a meter away from him could not connect. while the same iPhone works in its network

That's where we start. Hours at 18/19, when the peak of people is launched in the
/interface wireless spectral-history wireless_interface_name console and shows us the result, and not the spectrum, which is essentially nothing.
Further, after it is approximately clear which zones we have in sadness, run
/interface wireless spectral-scan wireless_interface_name adding show-interference=yes
There will also be indicated types of interference

bluetooth-headset - bluetooth stereo headset (headphones);
bluetooth-stereo - audio transmission via bluetooth;
cordless-phone - radiotelephone;
microwave-oven - microwave oven;
"cwa" interference
video-bridge - video conference;
wifi - Wi-Fi devices.

Also on ticks, you can monitor normally at what frequency they pump the most.
It's not very clear from your chart.
It's just that if there are a lot of people at certain frequencies, but they essentially always do nothing, then it's better to go there than where there are few - but they pump constantly.
Well, further teak can be configured to work in very bad conditions.
In general, you should not have produced a bunch of different vendors, but bought 2 more ticks and made seamless roaming by lowering the frequency (yes, lowering it, not twisting it). Then you would stop catching interference or reduce it.
The fact that he doesn’t catch close to you indicates that the channel is noisy and you may have turned the decebels to the maximum and the tick is yelling so that it doesn’t hear itself well, that it yells.
Try specifying like this. long you can try the same.
Reduce the signal level to 17.
Try to specify data rates of 1 and 2 megabits and remove them from higher speeds.
But in the end, there is no magic button to do well. Just like this, trying to understand by analysis what is happening in general and what kind of M interferes.
about 5 . Since at this frequency the wavelength is shorter, the attenuation is faster.

Take the popular frequencies 2.4 GHz (wavelength 12.5 cm) and 5 GHz (wavelength 6 cm). We see the confirmation of the rule on the example of the passage of a forest. The standard sizes of leaves, trunks, tree branches, on average, will be less than 12.5 cm, but more than 6 cm. Therefore, the 5 GHz WiFi signal will “lose” almost completely when passing through dense foliage, while 2, 4 GHz will do better.