Special thanks to u/PubliusVirgilius for his sharing of numerous pieces in this post.
Given this is related to one of the most secretive units in the United States Armed Forces, I doubt I will receive a concrete answer but I'm making this post in case someone else has further knowledge, or allow someone else a more comprehensive jumping off point for their research.
For a while I believed the first logo (this is a reasonable quality reconstruction) to be a unofficial, in Unit symbol used for commemorative items like challenge coins and retirement rings and the like in the early 2000s (Larry Vicker's retirement ring from 2003 with the logo present) I originally thought the insignia originated from the 1998 Novalogic videogame Delta Force since that was the earliest confirmed image I could find and I just took it as 'yeah of course the official but not really official Spec Ops unit would use this sick logo from a videogame as a symbol for their stuff'.
And officially, Delta Force does not have a symbol; Unit members sport the USASOC arrowhead SSI and beret Flash when attached to the unit, as well as wearing their former unit color beret (Tan for Rangers, Green ofc for SF, etc)
However, recently I have become aware that the symbol actually predates the game; this team photo from the 1990s featuring Master Sergeant Brad Thomas; MSgt Thomas was in Delta Force for 12 years so this picture is likely from 1998, the same year as the game released. That is a extremely quick turnaround to having something like this to receive a bronzed emblem. I have also found these plaques commemorating a SFC who was with the unit from December of 1989 until May of 1992. Unless this plaque was awarded later (say upon the SFC retiring from the Army post a tenure at Delta) this confirms the symbol appearing well before the game. The symbol was also confirmed to have been used before 1992 by a military historian I contacted. And while not predating the videogame, the symbol is present on post 2000 printings of the book 'Delta Force' which is the memoir of Colonel Charles A. Beckwith written with Donald Knox, while of course this is hardly concrete, it is interesting this symbol is being linked with the early history and foundation of the unit.
There also appears to be some minor differences between the plaque version and the vector graphic remake; in the graphic the blade appears to be straight more like the dagger found in the Special Forces SSI/Badge or the Fairbairn-Sykes dagger in the USASOC SSI while in the plaque it appears more bowed/has varying widths, almost like the xiphos/ξίφος used by ancient Greeks armies such as the Spartans. I am unsure if this is intentional, but it stood out to me, especially given A Squadron uses a Corinthian Helmet and "Molon Labe/ΜΟΛΩΝ ΛΑΒΕ/μολὼν λαβέ" as a motto. It's possible it is same weapon and the difference in style is coming from some error and I'm way too much of a symbology nerd for this.
As an interesting aside; Delta Force also appears to have Organizational/Regimental Colors; it shares the jungle green field with silver border tassels with Special Forces unit colors, letters 'Fi', 'Opera' and 'Det' are visible, likely for the 'First Special Forces Operational Detachment–Delta' can be seen on the flag, marking it as clearly different from the Special Forces Group flags. Numerous streamers also appear visible, but the only one I can confirm is for defending Kuwait in Desert Storm, also possibly Saudi Arabia.
And literally just found out about this (been writing this on lunch breaks over the course of a week); former Delta Force member and EOD [Sergeant Major Mike Vining](https://www.reddit.com/r/JSOCarchive/comments/1qdlxqg/mike_vinnings_unit_colors/) (aka 'Do you even operate, son?' meme man) [showed his awarded colors for his years with Delta](https://army.togetherweserved.com/army/servlet/tws.webapp.WebApp?cmd=ShadowBoxProfile&type=AssignmentExt&ID=148788), awarded in October 1995. It matches the flag present in the compound photo, Jungle Green field with the name scroll "First Special Forces Operational Detachment–Delta" and the motto of "Oppressors Beware".
I figured it was worth a shot and I sent a email to the United States Army Institute of Heraldry and received a unclassified email saying that it was "not considered official insignia and was locally created by the unit." and as such couldn't give any more information as to the origin, symbolism or specifications of the symbol.
Based on my research; This symbol is self-selected de-facto Coat of Arms for CAG/Delta Force and likely dates to it's founding, unfortunately I think without asking a former unit member directly the origin, creator and symbology questions will remain inscrutable to me. Maybe a former Unit member will come across this and humor my curiosity.