Search for a different server. Menu -> Social -> Search for a better server (or something like that)
You can only do that though as far as i know when the "wifi" symbol is red. And it's not guaranteed that you will get a better server next time. So you may need to try 2-3 times to get one with decent latency.
Could be server side or poor internet connection.
Test the speed,latency of your internet outside of gaming sessions. If it's bad, it's most likely your internet that's causing you issues. Try restarting/resetting the router etc etc... if doesn't work call your provider and try to sort the issue out.
Besides now a lot of people are working from home, i'd say overloaded networks could be one of the reasons why you have issues. And it's not something you can do something about.
If your internet checks out, the speed and the latency is satisfying enough, then the problem is on the ubisot server side. But i doubt it would be like that all the time.
I get some lag spikes occasionally for 1-2 seconds but that's it.