Lan cable connection but still laggs! What can this be?

I own a 100k line and even use a cable but it always comes back to short ping jumps from 20 to 400!

Unfortunately, my wireless router is too far, which is why I use a repetier (Fritz Repeater 1750e)

The gets full signal and is connected via LAN cable with my ps4.

Nevertheless, laggs have been around for a few days and have never been so far.

What can this be and what can I do to fix it?

It may be that the LAN cable is too long. Or it is too little power

If your PS is not directly connected to the router by cable then probably the wireless via the repeater or is it the whole distance to the game server… There are many factors involved