The router cuts speed only for my computer, how to fix it?

Question

network hardware

There is a Zyxel Keenetic Lite III router. Before the repair of my computer, the wi-fi speed was excellent. Now the maximum is 1.15 Mbps. Other computers on this network have excellent speeds.
What is strange, when I connect to another network, the speed is excellent, but when I connect to the network of this router, everything is slow. What could be the reason and what are the ways to fix it?

Answer 1

according to what standard is connected via wi-fi? bgn ac?
usually, this can be seen in the properties of the wireless network, the item "Speed"