I would not hesitate to use the 375 on buff. It's the best "one world rifle" I have ever used.

I have used and owned 416s, a 404 Jeff, three 458s, and a 460 G&A, as well as a 505 Gibbs.
I like the big guns, but I think the 375 is the best of the bunch, for an "all around rifle"

I would not even half-step.

Now your 458 is probably as good if you can shoot it as well. But that's up to you to decide.

I stick to my “6 inch rule”
6" target.
5 shots
5 hits

At the range you can do that------------- that's your personal effective range.
It varies, ---- depending on the man, the gun, the load, the shooting position, and light, and so on.

As for me, if I was to take my “6 inch rule” test, shooting from 5 yards to 300 yds, from 4 positions , over varying ground, at various times of day, I have no doubt I would do best with my 375 out of all the rifles listed above.