Phantosmia is real. I smell smoke that isn't there, often enough that I have to double-check with my husband that the house is not on fire. (Anosmia is the loss of smell - a symptom, now, of COVID-19.) You and I are lucky - smoke and roti, or even a gag-inducing air freshener, are better than feces and decomp, which are commonly smelled by sufferers, often when sniffing food or flowers or things that ought to be pleasant.

I don't think, though, that what you're describing is phantosmia. It seems more like an olfactory hallucination, possibly part of your dream. I am occasionally awakened by an auditory hallucination - usually a deep, male voice in my ear. On one occasion, I'd been having an awful nightmare. I heard the voice, and then I heard the doorbell. The doorbell, as it turns out, was probably real; as I looked out the window, from upstairs, I saw a woman walking away. But she was walking away across an open field that led nowhere. Was she also a hallucination? I know that I got out of bed and walked to the window to see who might be outside - it was probably 2 or 3 am - and that's what I saw, quite clearly.

My "multi-dimensional" involves recurring dreams that take place in the same place, with the same characters - mostly people I've known in the past, but doing things and living lives that might be described, by a Sci-Fi author, as being on an alternative timeline. I know them and they know me, but none of us are the SAME as we are in this timeline.

I may write about it, one of these days, but as you say - it tends to fade in the waking world, like looking at a star. You can't see it, head on, but it shines clearly if you look away.