The game just isn't fun anymore

I mean, you hit the top tier levels of players. Its definitely going to feel like a wall, but I'd recommend looking at what specifically is beating you.

Is it army composition? Are there specific units that tend to beat you more than others? If so, start packing better counters. Pay attention to the units that are kicking your butt and bring stuff to kick theirs.

Is it macro strategy? Are you losing to more aggressive or defensive strats? If you tend to lose to defensive strats, then try to be more aggressive. If you lose to more aggressive strats, then up that defense. How about production? Are your opponents producing the exact counters as you are producing the units? If so, switch it up and produce the counter to the unit of the unit you are about to produce. Step up those mindgames!

Is it micro strategy? Are your opponents positioning their units better? Pay attention to the choices they are making and adopt those movements/placements in your future games. Move your units often, send rocks to soak damage from other rocks before you send your paper in.

Is it unit levels? Do your opponents have much higher unit levels? If so, take into account you are punching up. That should make the losses sting less and the wins feel sweeter. Focus on levelling the units you use the most.

You should be proud you made it to level 10 and are in the top percentage of players. It would be kind of boring if it was easy even up there. Take the time to learn and get better. Losses still give fuel, which gives more cards, so it isn't a total waste of time when you lose.