Also, who are you testing this deck against? You said you dont play online so that means you likely cant play in tournaments.
I also question this. With no legitimate results to base the claim of Cursola being "the best deck in the game" on, it makes the claim even less credible.
This card is broken with Ear-rining bell, 4 dolls & 4-4 Cursola. I built the best deck in the game right now with this card! Play zero other Pokémon, just 4-4 cursola!
I'm honestly shocked you've won games with Cursola. The card is pretty terrible in terms of competitive play seeing that your entire strategy relies on flipping coins to not lose. You get bodied by Dragapult and ADPZ can just attack with Guru and Jirachi to win. I also fail to see how you ever beat Baby Blowns, Control/Mill or just any good player unless you just get
absurdly lucky. 60 damage isn't nearly enough offensive pressure to stop your opponent from just setting up whatever board state they need to win. Ear Ringing Bell also does nothing since every deck runs 4 Switch, most of which also run heavy Net counts. And this is already assuming your opponent either isn't playing Scrapper or doesn't have a way to find it on a turn they KO a Cursola.
On a different note than the archetype's issues, I think your list is extremely unoptimal. You have no way to combat hand disruption since you don't have a way to dig for resources other than hard supporters for turn. You also have no backup plan if your opponent knows how to play patiently and win with whatever archetype they're playing.
I also fail to see why you would play Cursola over TEU Beedrill. You already run the Rosa engine, but Beedrill guarantees KOs when it's active, has the ability to play Jirachi and other consistency mons that this can't afford to play (for gusting reasons), and has access to cards like Net Ball and Turffield Stadium. Beedrill is already bad, but it doesn't suffer from most of the issues that Cursola does. And the same issues it has as Cursola, namely consistency and the Pult matchup aren't nearly as bad because you have more consistency outs than Cursola. And for Pult you have Spiritomb and Rainbow already (because Spiritomb + Jynx sets up Destiny Stinger for a Basic Grass as well as the straight Rainbow attachment). It isn't reliably beating Pult at all but it's definitely more than Cursola has since Pult usually plays Swell, rendering Sky Pillar effectively useless.