I've heard a lot of unsourced (without actual on panel feats) claims that Darkseid hasn't actually shown up in person since COIE, and didn't reappear with his full power/without the use of an avatar until Final Crisis.
There have been images, I think, from Mark Evanier's New Gods work that shows the New Gods of Apokolips and New Genesis as giant beings that could easily destroy a planet, and their avatars are actually created by boom tubes. This also happened in a Supergirl comic, where she fought some of the gods as large giants on Apokolips.
I've also heard that after Grant Morrison got his hands on the New Gods, he retconned all of their appearances and claimed that they never actually appeared in full form (or, at least, Darkseid didn't) until FC, and Darkseid's true form is this thing:
So, does anyone actually know how the New Gods, or at least Darkseid's, avatars work? How powerful is the true Darkseid and what feats does he have? Are the pre-crisis Darkseids, from Great Darkness Saga and original Kirby stories, avatars too? if that's the case, were the stronger feats of Darkseid, like the feats from Great Darkness Saga, fighting the spectre, transmutation/cheating death (Justice League 183-185), and timeline manipulation, just really strong avatars?