Does the input delay / lag change irregularly?

Hi I'm playing Fortnite on the PC and my input delay / lag changes irregularly. For example, I had a very low delay for 1.5 weeks and now suddenly it is much higher and somehow not playable. It sucks. I haven't changed anything

It's mostly due to Fortnite, it's no different for me

Really?

Also on pc?

Yes, I'm on the pc, too, it is the same with the pros with the best pcs, fortnite is almost always to blame

So annoying without a joke

Honestly like that