Thank you for the explanation, but TBO, I still find the definition of NTR elusive after reading your post, perhaps as you stated: the definition is subjective to the reader. That's the reason why I suggest abandoning the confusing Jargon and using plain English instead.
This is a good point, but I must admit that I'm not sure if the discussion has already developed that there, but NTS is
NOT straight up cuckholding; in a sense yes, in another no.
I suggest giving a look to the game Stains of blue, its just a demo so very little to play, but it gives a good description to different shades of "NTS"
https://f95zone.to/threads/stains-of-blue-v1-6b-beta-zetzsuu.266838/
To give you an example of a different context:
Rough sex, is not bodage.
Spanking is different than bondage, as "soft" spanking is different than "hard" spank (spanks till your ass cheeks are so stupidly sore and filled with livids and broken capillaries).
One spanking game can be a sexy game of a rough fucking session, the other is straight-up hardcore masochism.
Are the two still spanking? Yes , they are, but there is an abyss between the two. This, without even starting to think about the relationship between the couple, as there can be intimate rough moments, or straight-up emotionless sex and submission, and so.
NTS and NTR are similar in fashion; both of those groups are appealing to an ENOMOURS amount of different shades of kinks, so you'll never find people to agree on it:
"Ah, it's too vanilla!"
"Ah, it's too stupid!"
"AH! It's too rough!"
"AH! The MC is just a stupid beta cuck, I want a strong male not scared to SHARE his women!"
"AH! It's all over the top, I just want to date a cute and affectionate
slut!"
And so on; I think its gonna be a kink that's gonna slip into many, many sub-categories with time. It all started with NTR, now its NTS, NTR and Netori, and I suppose it's gonna be further developed.
Just for the NTR aspect of things, are there 3 or 4 different and "community" (japan community) accepted type of different NTR settings