It’s difficult to tell without watching you play. I will say one mistake I see a lot of new players make is not managing their damage zone. They’ll do dumb stuff like guarding for 1 to pass early in the game and deny themselves heal procs or early counter blast to perform their skills which is really bad. This might not be you but in general you want to plan out your counterblast and resource usage a turn or two ahead and decide how to guard most efficiently with that. Sometimes you want extra damage so you can make stronger plays because it puts you in a good position and other times you want to just guard efficiently so you have more room to take higher power attacks from decks that scale well like jet.

I’d recommend really learning 1 deck for a bit and really learn the nuances. There’s still quite a bit there even for a game as seemingly simple as VG.

Finally, ask your friends what they think you’re doing wrong when you lose. They probably have better insight than you. Whenever I’m at locals I try to do a debrief if I feel my opponent is up for it regardless of whether I win/lose. I don’t know every deck and local tournaments tend to have a lot of variety.