Web shield and probably file scanner were causing troubles.
Secure line VPN removed ony my pc and deffault settings on mothers laptop.
All pages were slow to load. Http/htps Video streams being interupted or even ended. Dissabling Avast doesnt change anything. only after removal everting starts to work correctly.

Replacing car is bad comparison. Car remain same. Only faulty part was replaced.
Car is now fixed and I am enjoying the ride.