@Freyrs_storiesIn my limited understanding -- and this may demolish the concepts just because I love to talk in unwarranted simplifications of exaggerated extremes -- perfect "close" 3rd limited and 1st person could be, in theory, very nearly morphed between by just use of a clever enough regex serarch/replace. The ground principles and information accessibility are the same.
However, 3rd limited make pov switching and narrative commentary supposedly slightly less jarring. Things strictly prohibited in perfect 1st person would be only awkward in 3rd limited. In practice it likely means that close 3rd limited and 3rd omniscient exist on opposite ends of a continuum of indirect viewpoints, where the parameter factor is subjectivity/reliability. Perfectly omniscient narrator is not allowed to lie to the reader any other way than by omission.
Perfect 3rd omni is a police report. Pure telling. Investment of narrator isn't required and only speculation about anyone's motivation or emotional state are allowed, even if presented as immutable facts.
Beyond that, a risk of omniscient 1st person lurks. In my opinion, any conclusions a 1st person narrator make about anyone's mind should be by definition be seen as speculative, derived from clues not normally consciously inventoried by the protagonist... but that is "too much telling" somehow?
The dictionary word meanings make what percentage of information transfer in live interpersonal communication? I think the assessment was about 5%, while 95% are non-verbal, such as tone of voice, expression, assumptions about emotions, body language, clothing, and other sensory and context clues only very few well adjusted sociopaths are consciously aware about (out of nothing but necessity, without access to intuitive emotion chippers they have to compensate doing it the hard way).
Further, aleast in my environment it is rather common to speak words in deliberate contrast to the actual message, or with situational meanings assigned on the fly, and it's not limited to obvious jokes told in deadpan. I was and still am made fun at for difficulties with this, despite six years of drama club training and such.
In first person, especially pseudo autobiographical, I would seek to capture that. But delving into the nonverbal language is a futile excercise in verbosity as it will necessarily run into cultural peculiarities that then would need further explanation along with thousand years of history and whole alternative spirituality.
So... a hyper aware 1st person is omniscient of the limited word model they inhabit in their own flawed mind and I'm rather in mood to defend that against any standards. But it may not be what's considered good writing.
I'm going to assume that swapping between 1st and 3rd is likely worse than the whiplash of excessive head hopping.
Quirky pov hooliganism I sometimes cath in stories I tell to myself is that the main story is told in 3rd limited, but then, out of the nowhere a scene, usually observing the protagonist without their knowledge, is told in fist person by someone who may or not been mentioned or return afterwards as a background character. Going to be flagged as AI generated these days, lol.
I doubt I have written any of these down, but there is one start where I would seek to retain that no matter what. It make obvious the background character as the true narrator, and then the details he tells about the protagonist (a much younger girl gradually exploring nudism in assumed secrecy and privacy) become creepy in their own right, and that's kinda, welcomed. Well, if anyone makes it trough that kind of mental gymnastics. But at very least it heighten my own enjoyment.
I don't know how other people would react to such a narrator's cameo. And, yes, it seemingly wouldn't be too hard to translate such scene to another 3rd limited view in the final version. But even then, in current concept it would remain sole isolated incident of leaving the protagonist's point of view, so why not make it jarring in purpose if it would be so anyhow.