HUGE Lag spikes

So here we go: i have this config: first Keenetic Ultra black one gets the internet cable with l2tp, it stays near entrance to my flat. In next room i have keenetic extra, it's working in repeater mode but recently I got an issue. For some reason i have huge lag spikes, ping could be 2-5k instead of 30 ms for example for no reason. Nothing changed but now it's impossible to play something online. If i connect right to ultra ping is ok. i tried to reset all the routers, changed settings nothing helped. Any tips?

#Others_July