@ SH
“Non Political,
Look it up, the early Chassidim davening way way after Zman Tefilah.”
I was bringing a halachic justification that actually had traction with (some) subsequent Poskim. The custom you are referring to was:
1) roundly condemned and ceased.
2) not as widespread as you are implying
But ok, if you want an early source for davvenning completely outside of zman see the Trumas HaDeshen re: Maariv. If you learn his teshuva you will note that how he deals with the issue is highly instructive.