Exactly. Just imagine a temple, see yourself, and do the ritual. (This obviously requires some developed imaginative and trance skills.) I started this from the meditation/hypnosis realm, so I just imagined it all in my head in a hypnosis vision of sorts. Now, I would describe it as astral, but I can understand why people argue the occult is all in your head. I now prefer doing the rituals in the world, but because I spent so much time doing it in my mind, I also drastically shorten the rituals in the world as I can pretty much sit anywhere and extend a strong circle/area. I also pretty much instantly achieved contact when I went to do evocation IRL the right way.
I haven’t noticed any heavy dangers or repercussions different from doing magick in this world. It’s basically like astral travel prep + trance/meditation work + learning the magick stuff. It’s also really helpful if your living environment is inhospitable to magick.
I imagine there are dangers in doing things this way, but pretty much everything is dangerous… I also work heavily with qliphothic energies, so I’m used to them rocking my world quite a bit, haha. You could do like a LBRP or call the elements/corners, use salt (IRL or in the astral), work with a deity you trust as an advisor (or do likewise with a guardian angel, higher self, HGA, etc.), talk about it to your higher guides, etc. But at least for me, I know that the most powerful work I’ve done is the stuff I’ve been leery to do.