In my opinion it's normal for some kids or people to be distracted easily or have more energy than others. They require more attention. Also a child's brain is not fully developed. Why do we expect all kids to be great at focusing? Do you think the focus is worth the reported short and long-term side effects[0]?
Dropping your starter attack and defend cards after getting better alternatives is a good tip for new players, but the number one factor in winning in my experience is selecting the right card combos and synergies. Identify possible combos early and pick future cards to build on those strategies. If a card doesn't fit in your deck skip it. Sometimes you'll pick a combo card early and not come across any synergistic cards and lose or have to pivot strategies, it just happens. Having a smaller deck with only the cards you want will usually help though.
I personally prefer javascript even with it's downsides. It's very fast for me to spin up a nodejs express server with sessions/crud API, and I primarily use the async/await style to simplify promise handling. I work with .NET Core apps at my day job but for personal projects I always choose nodejs due to simplicity.
[0] https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=aff...