Viper’s not really a good online character. You need the game to play smooth to dictate things with her correctly because her seismos have pretty slow start up compared to most people’s normals. Once you get the seismos out there you can get going but until you can get one out you’re susceptible to them mashing on something and blowing you up.
If you’re playing C.Viper/Doom/Strider like it says in your sig (and we’ll just pretend you’re actually playing offline for once) then you kinda just have to know what to do based on the matchup. I personally use missiles so any rushdown character I basically usually just blow EX seismo start of the round and call missiles to get space. You can also do H thunder knuckle throw option select if you’re close enough to them. I’m not worried about burning a meter since the idea is to get enough space to chip them down with stuff so a very basic combo will kill them off any way. If I desperately need the extra damage I’ll TAC infinite into Doom if I’m close enough to the wall or try to set up a reset.
Once I get space I try to call laser often to keep their assist off screen and mix it in with seismo so it keeps the point character from moving also. Then keep that going while missiles are coming down.
If they start to get in focus attack into H thunder knuckle, ground throw or EX seismo is your main tool to deal with durpy normals. Viper gets shitty normals but trades it for being the only character in the game able to not be put into a combo as long as you hold two buttons down. Which if you have a projectile assist coming out during that time can clear shit up also.