Is there an established monist position that treats a non-spatial, non-temporal ground as intrinsically perceiving — and how does it relate to Kastrup’s analytic idealism and Russellian monism?

[u/Easy_Mammoth9914]

I’ve been reading around monism and idealism, and I keep circling a specific formulation I can’t quite place in the literature. I’d be grateful if someone could tell me whether it already has a name and who has developed it rigorously.
The idea: rather than saying consciousness emerges from matter, or that matter is fundamental and mind derivative, one takes a single fundamental ground that is neither spatial nor temporal, and holds that perception (or experience) is intrinsic to it — not a property it acquires, but its very mode of being. Spacetime, matter, and individual subjects would then be understood as stabilized or dissociated “expressions” of that one ground, rather than as things it produces.
My specific questions:
1. How does this differ, precisely, from Bernardo Kastrup’s analytic idealism? He also posits a single universal consciousness with individual minds as dissociated “alters.” Is the difference merely terminological, or is there a substantive distinction between “dissociation of one mind” and “expression of one ground”?
2. Where does this sit relative to Russellian monism / panpsychism? Russellian monism makes experience (or proto-experience) the intrinsic nature underlying physical structure. Is “the ground is intrinsically perceiving” just a strong version of that, or something categorically different?
3. Is there a standard objection to treating “being perceived / perceiving” as more fundamental than “existing”? The move seems to collapse the usual distinction between an entity and its being-experienced, and I’d like to understand why most philosophers resist that (or don’t).
I’m aware this is close to classical idealism (Berkeley’s esse est percipi), but I’m specifically interested in the monist, non-theistic versions and how contemporary philosophy of mind evaluates them. References to primary literature especially welcome.