This is very 3D specific.
We have a situation where there are multiple Loona/FNAF/other models that I feel should have modeller tag. My argument for tagging modellers is that people may like a character but not like a specific model of said character or they might want to see a specific model.
For major characters like Loona, it's unnecessary to use Loona_(owner) since the owner is in the copyright section. For smaller characters, there is an issue where there can be 2D art of them 3D art such as is with medivh_(soundvariations) which is character_(owner) so you could make the argument on should the owner be in the tag or modeller, however for small characters like this it's unnecessary to have any parenthesis tag as they would almost never have a second model of their oc. For those specific rare cases, it would have to be taken as they come.
There is also an argument that what if you have, say, a 3D model Link but it's not Nintendo's Link but an OC Link not related to the Zelda universe a all. You wouldn't be able to tag it as Link_(modeller) because that assumes that it's Nintendo's link since there's no owner [Link_(owner)] and you also can't tag both. A solution to this would just use Link_(owner).
But now you see a new problem. Can we agree to use a character_(owner/modeller) in the same format? I think that's the best compromise vs not having a modeller listed at all thus not being able to blacklist/search for a specific model, and not having to figure out how to put the modeller in the meta tags since you're not supposed to put the modeller in the artist tag since they're not the one who made the image.