Post MacOS Ventura update, my internet speeds has went dead slow. Even web page loading was taking loooong time. I found a lot of articles that recommends the different kind of fixes like Removing and Adding the Wifi Network again, clearing DNS cache etc. That may work in normal cases. But if you have Kaspersky Internet Security installed on your device, the issue may be related to IDS content filter. I have read somewhere that Kaspersky is yet to update its support for MacOS Ventura. When I disabled the IDS filter, things have went back to normal and I was able to experience swift page loading.
Here is what I have did.
Went to Settings >> Network >> Filters
Disabled Kaspersky IDS filter.
Even though its not recommended to turn off IDS filter, as a quick fix you can try it now. But always keep a watch on the Kaspersky updates and apply the same as soon as it get released. Post that, return back and activate IDS filter.