My son has used a 223 on moderate sized to small deer and antelope with great success, when starting out. Once he grew a bit, he moved on to a larger caliber. Heart/lung shots with a bullet designed for deer is what we have done. We've had good results with the Federal Fusion bonded 62 gr. factory load. Several bang flops, but nothing much over 225 yards, most much less. Largest animal maybe 200lbs, most under 160 lb ish. Will probably start the grandkids with a 223 too, until they grow a bit (can start them at 9 in OR), then move them to a 243, 250 Sav., or 257 Roberts.
I do have some friends in MT that hunt large mulies with the 220 Swift, out to 400 yards +, and have for decades. They shoot coyotes with the same gun too, they are great shots, shoot all year, and are very picky about when they shoot, not my cup of tea, but works for very well for them.
That said, something in .24 or .25 caliber is a much better choice IMO for a spouse, as a combo rifle, especially if seeking a larger mature deer and shooting much past 200. I shoot coyotes with what ever is at hand, like TS, not much concerned about the pelts, so am no help there.