Ahh yes - the "inner sanctum" or "astral temple" - which you then take yourself off into for numerous purposes (path working) - some peaceful meditation, to converse with your guides or the dead, to commune with your Deity, to explore the astral plane, to work magick (healing or otherwise), etc...
As mentioned - it's a meditative practice to visualise such a place.
And it's not scary at all - as it's all of your own making.
I have one, a tall tower (7 levels because 7 is a significant number for me, as well as reflecting "cycles of 7" and the Western 7 major chakras in relation to life growth. Plus there's always gold at the end of the rainbow - right?
with a whole surrounding landscape complete with various creatures in it.
And - I ride a giant Lammergeier https://en.wikipedia.org/wiki/Bearded_vulture
(not a dragon
Plus I'm often kitted out in magnificent battle dress - with a life-size version of my favourite Athame (ritual dagger) as my short-sword.
I am Wiccan.
When I was still "in the closet" (as a Wiccan) - I used to do my rituals "in my head", creating my sacred space in a favourite section of my parent's back garden.
And from this, my whole "astral temple" and landscape grew over time, as I was introduced to the idea through various meditation groups and books.
(Physically - I would lock myself in the bathroom whilst doing this, and soak - the one place I wouldn't be disturbed).
Did you decide this, I mean the kind of imaginary temple you would like or is this something revealed to your mind in some way?
It's a mixture of making the scenery up yourself and seeing what spontaneously arises whilst you walk around in it.
I know nothing of the Buddist "pure view" - but I suspect it's not the same... That sounds more like an exercise in appreciating the amazingness of reality - to better cultivate a state of loving kindness...