Panspermia: Not proven in the general case, any more than it is today, and probably substantially less – different evolutionary trees and biochemistries surely look as if they had different origins.
Confirmed in some specific cases – Eliera, for example, derives its life from three sources: bluelife, which is very clearly descended from the native life of Revallá (Imperial Core); greenlife, of unknown but extraplanetary origin; and silverlife, descended from feral Precursor nanomachines – but then, Eliera is an artificial planet, so that’s to be expected. And many garden worlds are the product of ancient terraforming, such as the many methane-based garden worlds in the vicinity of the Elmon Rift that were terraformed by the ancient and extinct methane-breather civilization that thrived there around 33 million years ago, and so possess life which obviously originated offworld.
But natural panspermia, or a common/intentional aliens-seeding-life origin? Very much not proven, and looking increasingly unlikely.