Just from my personal experience with my family. In general my kids and wife never cared/noticed 99% of the upgrades I made to the family PCs and over the years I learned to reuse and pass down parts from my gaming or work builds. Kids especially wont care about load times, most gfx settings, etc etc and just accept it works and looks cool.
1) Consider waiting for upgrade to 1060/570 on sale sometime in new year. Since the RX590 came out 4GB RX 570 sales have dipped as low as RX460 prices and 1050 is not really worth it unless you have an old or get used one cheap. Maybe nab something cheap for Canadian boxing day.
and
2) you can then nix the GPU. Downgrading to iGPU gfx on a Ryzen 2400G might be a better bet for kid games at 720 high or 1080p low/mid settings. Makes for a nice small and cool build (htpc).
3) Since its a kid system, perhaps dump in old HD from your PC and upgrade your system to SSD/NVME or bigger backup. Or use old spare.
4) consider passing down some of those savings towards mini-ITX motherboard and a mini-ITX cube case if the system doubles as htpc. If in half a year or year you decides little guy/girl needs more FPS, can still buy and fit a GPU to max framerates at 1080p 60hz for most games.
ASRock - B450 GAMING-ITX/AC Mini ITX AM4 Motherboard (B450 GAMING-ITX/AC) - PCPartPicker Canada
Thermaltake Core V1 Extreme Mini ITX Cube Chassis, Compatible with air and Liquid Cooling Builds (CA-1B8-00S1WN-00) - Newegg.ca
Lastly, consider:
"Look kid.... it loads 10 seconds faster! whoa!"
or.....
"Flashy RGB lights"
5) What kids will LOVE (mine all do)!.... RGB lights!
Get some RGB ram, RGB cooler etc, and a case like the Thermaltake that has a Window so they can see it *breathe*. If you have a cleanish build they will see the lights well, especially at night.