I don't see any blatant incompetence from the Germans in Op. Bagration.
What they certainly had was an absolute lack of means and so couldn't do much against the Red Steamroller in full swing anyway, even discounting their playing mind games with the Gemans with their Maskirovka and fooling them as usual.
Just look at the comparative Order of Battles and see if they had any chance. They did the best they could improving what was already defensive terrain (it wasn't a picnic for the Sovs for that reason), so I can't honestly fnd reason for Incompetence here much to my chagrin.
The Germans fought well, the Germans fought hard, but when the Sovs put down D-Day as the Barbarossa Anniversary, well, they had to mean business.
Read
this and
that for the time being, and Steve Zaloga's book from Osprey is also a very good intro.
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"Do you mean the Asiatic hordes driven forward under the lash?
Oh, sorry, those were the Persians described by Herodotus in the 5th Cent BC!"