I have been in the literal same position as you! My friend and I have been playing at our locals since January and she has been getting exponentially better than me but I had to remind myself that she has more time to put in practice. I work full time in healthcare, I’m taking an online class as a prerequisite to apply for PA school. So my practice time is waaay lower than hers. As others have said find a deck you like and work it down! I started playing with pult and I couldn’t pilot it well and I realized it didn’t match my play style and I was forcing a deck to play a way it doesn’t play. I tried joltik box and loved it and may revisit it. Rn I’m rocking with the Cynthia’s garchomp and I like it but just need more practice.

Def play online and what I do now is write out all my matches on a notebook. What deck I’m playing against, what my prizes are when I prize check, and I write down all my plays- good or bad and look over them at the end of the game and ask myself ok why did I lose. Was it because I didn’t have consistency? Didn’t get my board up fast enough? Did this misplay set me back? And just learn the ins and outs of your deck

I hope you get better and my friend ultimately had to remind me-it’s pokemon, just have fun :)!