Wifi Spikes to 500+ms when Iphone is charging

Hello,about few months ago I bought Iphone 7+ 256GB from a Friend

And from time to time I started having Ping spikes to 500+ etc( at the time I Didn't know it was Iphone always thougt it was something else like My dad downloading smth or etc,but he always said he isn't downloading so it was kinda weird.

Today I found a question on internet from 2013 some guy on internet that he had a problem with Iphone that was charging that make his internet spike to 1000ms when on stand by for 2 mins ,right after he unlock the phone the internet would go down to normal 50+- ms

When I tested the same thing today charging phone and the phone on stand by for about 3-5mins the internet(wifi) connection would spike up to 500+ ms and it would stay there until I would unlock my Iphone,then the Connection would fall down to normal 50ms ping.

Did someone had the same problem?

Is there any solution to this?

I really would like to fix this,thanks!