As it happens, I believe I’ve heard something in the distant past, to the effect that ED, at least at that time, used deferred rendering for some things, and forward for others.
I have no idea how many separate layers the game renders and composites together, but it is always safe to assume that UI elements are done on their own, and I quite suspect planet surfaces may be done in one pass, and every object, that may appear on that surface, in another, because if one push graphics fidelity to the point frame rate gets really low; One can move one’s head around, and actually see motion lag between surface rocks, buildings, SRVs, and so on, and the ground they are supposed to be… ehm… “grounded” to, which could be imagined to mean the layers have even been set up in such a way that their rendering is allowed to cross frame boundaries, rather than only being a floating point precision thing, between recusions of coordinate system parenting, which Elite also exhibits a lot of (take, for example, a trip with the vanity camera, e.g. when docked at a station, and check how the camera being parented to the ship, which is parented to the landing pad, which is parented to the station, leads to whole sections jittering around, relative to one another, when viewed up close, and the mantissa is not fine grained enough). 
Planet surfaces have also so far exhibited less aliasing than “loose” objects, to my eye, which could be construed to suggest they are rendered forward and receiving the proper multisampling antialiasing one can not have with deferred, but that could of course also simply be a matter of how the heightmap topography tends to be be kind of soft and rounded, with texturing (with anisotropic filtering) carrying most detail, whilst being similarly soft and low in contrast, which could kind of attenuate the “standing-out-ness” of any jaggies.
As it happens, it has been noticed (well, it stood out to me, at least) that the new more detailed planet features seen in ED:Odyssey promo videos, exhibit a lot more aliasing than what we have previously seen on planets. This could simply be the inherent effect of the aforementioned difference between old low frequency detail, and new high frequency detail, BUT one could also couple it with something that was said in a Q&A with one of the planet generation/rendering developers the other week, that more stuff now will have “physically based rendering” materials. -Spinning on, on that thread, one could conceive the notion that planet rendering could be about to transition from forward rendering to deferred, in line with the rest of the game, which would subject it to the same drawbacks as all the “hard” objects previously in that pipeline.
That, however, should potentially come with the associated upsides to deferred rendering, and maybe we could finally get lighting from multiple stellar bodies - a long desired fundamental feature, even if maybe shadow maps could be presumed to remain from a single global source (plus one local one), for performance reasons; As well as, on the PBR side, more shiny ice, to offset the additional specular aliasing that is bound to come on the other side of that coin, as you get into recursiveness and resolution sampling matters between normal maps and reflection maps… :7
An old engine that is modularly designed, can always have bits swapped out and updated - even should it turn out to be Gamebryo. :7
(EDIT: So if things are about to go from bad to worse, jaggie-wise, maybe we could hope for a some good implementation of TAA or DLSS to soften the blow, although I am not convinced, neither of the prospect of FDev doing anything of the sort, nor the output quality of such algorithms… :7)
Cobra engine.