How to make friends Mikrotik with mobile phones?

Question

Mikrotik

Hello
Houses cable Internet 100Mbps.
There used to be an ancient tp-link 741nd of the first revision with openwrt. I decided to upgrade to Mikrotik RB951G-2HnD
As a result, in the next room (through the wall at the opposite wall), my brother's speed increased to 70-80 Mbps on an ancient laptop. And on my old tablet and Xiaomi Redmi Note 4x (2017), the speed dropped to 18-20. On tp-link 741nd it was 40-45.
I updated the firmware, OS. Left only N mode (although in ps3 - G). Then I lowered the transmitter strength to 18db (by default there are a lot) according to the advice in the article. All the same, the speed on mobile phones is 18-22.
By cable:

Answer 1

I solved the problem by replacing it with the ZYXEL Keenetic Giga III.
Although I also had to suffer with it, because there are 20+ networks on the air and all are 40 MHz. There are fewer settings in it even than in tplink.
His antennas are much weaker, but on mobiles over N in the whole apartment, the speed = 40-45 Mbps. Ac 75-80. On the air 20+ networks at 40 MHz

Answer 2

Mikrotik and xiaomi are not good friends with everyone, you can’t do anything about it yourself. We have to wait for a fix from the manufacturers themselves, and they poke each other