What theory?
The Reichswehr was ordered by the Ministry of Defence to use the Nazi Eagle on it's uniform begining 1 May 1934. The same month the Reichswehr was retitled the Wehrmacht Heer as Hitler followed through on his promises to expand the Army.
The Wehrmacht was a creation of the Nazi Party and wore it's symbols as part of it's ceremonial and field uniforms.
Anything else is "lost cause" revisionist bullshit.
1935
1944
Also from wiki:
Die Vereidigung der Wehrmacht auf Adolf Hitler, 2.8.1934
"Ich schwöre bei Gott diesen heiligen Eid, daß ich dem Führer des Deutschen Reiches und Volkes Adolf Hitler, dem Oberbefehlshaber der Wehrmacht, unbedingten Gehorsam leisten und als tapferer Soldat bereit sein will, jederzeit für diesen Eid mein Leben einzusetzen."
The Wehrmacht Oath of Loyalty to Adolf Hitler, 2 August 1934
"I swear by God this sacred oath that to the Leader of the German empire and people, Adolf Hitler, supreme commander of the armed forces, I shall render unconditional obedience and that as a brave soldier I shall at all times be prepared to give my life for this oath."
There is a list of public notables who refused to swear an oath to Hitler either in public office or conscription to Heer/SS and their various punishments including death penalty.
https://en.wikipedia.org/wiki/Hitler_oath
The Wehrmacht as a organisation went along with this shit, German army officer drafted these oaths from within the defence ministry(General Werner von Blomberg and General Walther von Reichenau). The Wehrmacht's very genesis after all owed everything to Hitler and the Nazi party