this is only advised for people with a lot of mobile data or unlimited
so what you can do is tether your phone to your pc and use your mobile data instead of wifi. your mobile data should be more secure/stable than wifi so you will get less ping spikes. your average ping will be higher by like 20-30 ping but will be more stable. works best with usb 3.0
ofc ethernet is the best solution but if you are too far from your router this might be a good fix for now.
edit - this also works if you just tether your phone to pc and use wifi through your phone. no data needed.