Set the embellishment apart from the narrative flow.
The POVchar's nattering along, & s/he spaces out, imagining all sorts of stuff that happens, maybe mundane or maybe hallucinatory (e.g. William Burroughs). Then the narrative snaps back to realtime, & we're once again watching the attested factual part, without having to intrude & treat the reader as stupid by saying "that was all imaginary."
If you need to "embellish" more than that, either write fiction-with-elements or a collection of essays. Else I'd suspect you're planning in order to avoid actually writing, which is fine so long as you admit you're stalling.
The POVchar's nattering along, & s/he spaces out, imagining all sorts of stuff that happens, maybe mundane or maybe hallucinatory (e.g. William Burroughs). Then the narrative snaps back to realtime, & we're once again watching the attested factual part, without having to intrude & treat the reader as stupid by saying "that was all imaginary."
If you need to "embellish" more than that, either write fiction-with-elements or a collection of essays. Else I'd suspect you're planning in order to avoid actually writing, which is fine so long as you admit you're stalling.