Question Pc lag

In warzone frame drop and latency increase
Frame rate is a hardware issue and probably has to do with your RX470. As I said that card is fairly weak by todays standards. If you updated the AMD drivers recently maybe roll back a version or two and see if older drivers are better.

Internet lag can be alot of things. If you are on wifi, then it can be a weak signal or interference from a congested wifi network (doesnt have you be your own network, even lots of other wifi networks like in neighborhood or apartment can cause problems) which switching to a 5ghz band may help if you are on 2.4. To rule out this or even a problem with your router the best thing to do is plug your computer directly into the modem with a ethernet cable and see if your over all connection is better.