My last PC I built Jan.2013. It was a Ivy Bridge 3770k.
And my current PC with a 3950x I built Jan.2020.
That means, 7 years difference.
I had an 27"-monitor from asus. Is a freesync-mon. and was one of the first monitors with "g-sync-compatible"-certificate from nvidia.
Take the 3300x.
One review: https://www.tomshardware.com/reviews/amd-ryzen-3-3300x-3100-cpu-review/3
I suppose, your son will be happy with it,...