This isn’t meant to be disrespectful, just giving my 2 cents worth, because I know what I’m talking about.
What’s good, or best for someone, is simply based on your needs, and explaining the little you’ve done, has only given us a glimpse for now, not everything.
You might be dying, and you want to just hurry up and build something, but if money is a concern, just look at the prices on Amazon, no joke, I’ve been buying and building my computer parts off of Amazon, there can be some really great deals.
Don’t rush it, take some time and do some home work, in the end, you’ll be better for it.
I know we are talking about a 10 year old and a few games, but rhetorically speaking, what about more games and the future?
When building, you want to make something that is going to be ‘Future Proof’, going to last a few years, and that is based on the types of games you play, the game settings, Med, High, Ultra, 1080p, 1440, good frame rates etc...
Now you might be saying, this is only for a kid and a few games, it’s not the point, it’s what are you wanting to get out of the games, quality and performance.
Some parts, are just a waste of money, so again, it depends.
I would never ask someone what to use, because everyone has their own preferences, and you should take the time to read and research yourself, to find out what suits your best interests, no one else.
So, since you mentioned building Intel, i5 are good for gaming, Ryzen 5, Asus, MSI, Gigabyte motherboards, I personally use Asus ROG.
Corsair, Kingston, Crucial Ram.
Corsair power supplies.
Noctua cpu coolers and for case fans.
Samsung, WD SATA SSD, or nvme if you want.
Graphics cards can be a tough call, seriously research them, I’m a fan of Nvidia, and 4000s are just around the corner.
Evga has the 2060 KO Ultra Gaming, on their site for sale, that’s a decent card, better than a 3050, and some lower end 3060s.
For a case, I just built a box with a Corsair 4000D Airflow, really nice case, great airflow.
When doing Air Cooling, finding a good air cooled case can be tough, but Corsair did a really nice job on this one, and really easy to build in too.
Have fun!