Ah! the age-old (since A Frame and mono metals slug appeared) NP question...
To make it short:
1--- On one end of the spectrum: elephant, hippo (body shots), rhino: solids only. No NP. Not even AFrames nor TSX. Period. (Although on a perfect behind the shoulder, double lung shot, I would personally prefer a TSX to a solid, but this reduces tremendously what shot can be taken).
2--- On the other end of the spectrum: lion and leopard chest cavity side shots: the NP is likely one of the best bullets available for this very specific job, precisely because it was designed to have the front core expand explosively in the lungs and not punch through. For this very specialized job, I believe that the NP outclasses the AFrame and TSX.
3--- In the middle of the spectrum: typically buffalo, a NP will do more damage to the lungs with a classic behind the shoulder double-lung shot (which WILL kill a buff very dead, thank you very much!), but an AFrame or TSX will penetrate deeper on about any other shot, whether big bones (e.g. shoulder) are encountered ... or not, due to higher weight, hence momentum, retention.
This is really simple, there is no free lunch: more explosive expansion and fragmentation causes more lung damages, while more weight retention penetrates deeper. Simple!
I would add that the modern "expanding solids" (e.g. TSX and, to a point, AFrames that do retain their mass) likely provide enough expansion while also providing enough penetration, but they do not provide the "grenade effect" of a NP front core pulverizing lung tissue.
Sure, one do-it-all load is great for the one-rifle general bag safari, and my own do-it-all .375 load if the 300 gr TSX, but, call me an outlier, I personally think that nowadays DG hunts are so specialized, that it does not bother me overly to re-sight with a NP for a specific cat hunt. Anyway, the PH is likely to ask you to do it, just to make sure that you are dead-on for distance anyway.
So, my personal choice of bullet for lion or leopard is the NP .375, but this being said, my PH insisted for me to shoot a .458 TSX and it certainly killed this lion very dead. Goes to show that there is more than one way to skin a cat (pun fully intended)
As to PG only, my first question would be: why use a .375 ?
Anyway, before the AFrame and TSX arrived (1984 and 1986 if memory serves?), since 1948 hunters around the world were worshipping at the NP altar and killed anything under the sun (and moon) with entire satisfaction. It sure beat the Kynoch soft and other Core-Lokt, Power-Point, etc.
One could even make the rational argument that unless you need to punch through 3 feet of meat (which includes the buff... and even the eland from any angle other than behind the shoulder side shot) it is better to expand energy within the animal rather than against the hillside after pass through.
But I will still add that even on a Kudu, the day you need that quartering-in chest shot or quartering away shot, or straight up the poop chute backup shot, you WANT penetration, which is why I now shoot TTSX rather than NP, and Lord knows, I shot ONLY NPs for 40 years...
Pick your poison in the expansion vs. penetration endless debate...