@TomoA 

You will need Deco model with "Added schedule and bandwidth limit to guest network" feature. You can find list of all such Deco models here: https://community.tp-link.com/us/home/forum/topic/597476

Note that some have firmware beta that you'll need to install manually, and some have production firmware that should be installed by Deco app. Pay attention to hardware version, this part is very important. For example, Deco X50 firmware V1.2 does not support that feature, while X50 firmware V1 does.

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As a workaround for Deco models that do not support that feature, you can run Deco mesh with only 2.4GHz enabled on Guest network (disable 5GHz, WiFi6, WiFi6E). That will substantially reduce WiFi speed of devices connected to Guest network.

  @Alexandre. Hi Thank you very much dor the answer. But as i wrote i have deco X60 model and i would like to use this one. Please it is possible to enable speed limit for guest network this model?

  @TomoA 

Deco X60 is not on that list.

With Deco X60, you can try workaround I suggested.

  @Alexandre. Hi thank you very much for answer. my last question is if is any TP link router that  allows one network like on deco (roaming) which allows spped limit for guest network? i would like to buy some TP link device and not other brand. i dont need exactly deco i just need solution where more devices (ap or extenders) creates just one network and of corse guest network. we have aprox 50 to 80 clients online . thx for answer