Problem with Loss and sometimes big response

Hello,
I have MikroTik hAPac2 version 7.2.3.
I have a problem with high latency to it from the local network over WiFi.
The WiFi power between PC and router is -66dbm. When releasing mtr to the router, there are a lot of pings at the level of 1-2ms, but they happen above 300ms to 4000ms, which makes the pages load for a long time.

It would be best to connect via cable, but I don’t have such an option.
Where can I start analyzing such strange delays to it?
Will only a separate AP somewhere closer to me reduce this lag?

Best Regards,
Bartosz