It sounds like the solution is really a 223 AND a 6.5 Grendel. My eldest is shooting a lower velocity load in the 7mm-08 and if I wasn’t so far into that cartridge (bought the guns for me not for the kids) I’d start the kids off with a 223 and hunting with a Grendel. Too bad Cooper doesn’t make the Grendel. I sure like their rifles. These are her first 6 shots ever with a cartridge larger than 22-250.
(I’m covering my fouling shots from earlier, her name, and incorrect load data I wrote down on the wrong target)