As for what the Ankh symbol is, as it was depicted in artwork in 1st dynasty period, as shown adjacent, be it a "walking sun", or what not, is not really known subject?
The gist of the symbol, however, seems to, as we can trace backward, from the "vis" of Venus giving "vita" or life to people (see: term reform), in Roman mythology, which was a rescript of the Greek goddess Aphrodite, which was a rescript of the Egyptian goddess Hathor, who was thought to be a cow-version goddess equivalent of the Milky Way, is that when the ankh is put to the mouth of Khnum's clay human figures, they are "bought to life":
Although difficult to confirm, the gist of the nature of the ankh, seems to be that the idea that it contained the air-moisture spiritual component of the god-goddess pair Shu-Tefnut (air + moisture) of the Ennead of the Heliopolis creation myth (2500BC version). The connections here, however, are a bit tenuous, as her connection with the Ankh dates to an early dynasty period, prior to the formation of the Ennead, when she was considered the “house of Horus”, which is what her name means, and sometimes said to have association with Shu. The gist of this being that just as the Milky Way gives conceptual so-called spiritual nourishment and life to the sun, so to does the ankh give life to humans, or something along these lines.
In 1904, Wallis Budge was referring to the following so-called hand-up version of the ankh as the "living Ra":
- “Nephthys is seen kneeling by the side of the Tet [djed], from which the disk of the sun is thrust upwards by the ‘living Ra’ at sunrise.”
- — Wallis Budge (1904), The Gods of the Egyptians, Volume Two (pg. 255)
Budge also stated that the circle amulet "", oft-seen been held by various Egyptian gods, was asserted by some to be "related" to the ankh, was the "emblem of the sun's path in the heavens and of eternity".
In 1905, Flinders Petrie suppositioned that the ankh was a male loin girdle worn around the waste.
In 2006, Peter Joseph, in his viral Zeitgeist, asserted the view, based on Dorothy Murdock (1999), and others, that the Ankh, in the context of astro-theology, is symbolic of the re-birth of the sun on the or at the position of the star constellation of the southern crux. This southern crux sun ankh model, however, does not seem to align with the older ankh with two legs depictions.
In 2016, Libb Thims was loosely conjecturing following is an image of the conjecture that the two-legged ankh (c.2980BC) is representative of the Khepri-Ra god (dung beetle rolling scarab) flying or rolling the new-born sun into the sky, the arms and legs of the beetle being the two arms and two legs of the Ankh of 1st dynasty Egypt:
In 2800BC, the was scepter, the symbol of Set (darkness or evil), was combined with the djed pillar, symbol of Osiris (lightness or goodness), with the Ankh, the breath of life amulet of Hathor, to make the three-in-one scepter of the god Ptah, as shown below:
The following are renditions of the ankh in the years 1350 to 1000BC:
In the first, we see Ra, inside the circle, as the morning sun, or Khepri (dung beetle). In the middle version, we see Ra being born out of the djed pillar or backbone of Osiris, which is known to us now as the angle being put at the top of the Christmas tree. In the latter version, we see the ankh, in human form, supposedly being Ra, standing next to Osiris.
The following are related quotes:
- “The origin of the ankh symbol has been debated for more than a century, but with little agreement as to how the symbol was derived. Most dictionaries and encyclopedic works refer to a popular hypothesis of the famous Egyptologist, Alan Gardiner (Gardiner 1928), who envisaged the ankh as a sandal strap. Little support for this proposition can be found, however, in epigraphic and iconographic records, as noted by Gardiner himself. While Budge (1925) and Chevalier and Gheerbrant (1996) speculate that the loop of the ankh sign likely symbolizes the solar eye of the sun-god Ra emerging from an eastern horizon, and others attempt to derive the distinctive emblem from the image of a penis sheath (Baines, 1975) or cow vertebra (Gordon and Schwabe, 2004). Egyptologists have yet to reach a consensus on the matter.”
- — Andrew McDonald (2018), “Influences of Egyptian Lotus Symbolism and Ritualistic Practices on Sacral Tree Worship in the Fertile Crescent from 1500 to 200 CE” (pg. 149) 
- Cross – Hmolpedia 2020.
- Dunand Francoise; Lichtenberg, Roger. (2006). Mummies and Death in Egypt (Ankh, ansate cross, pg. 215). Publisher.
- Assem, R. (2008). “Article” (pg. 18), Bulletin of the Egyptian Museum. American University at Cairo.
- Budge, Wallis. (1904). The Gods of the Egyptians, Volume Two (pg. 244). Dover, 1969.
- Whatham, A.E. (1919). “Phallic Symbolism” (§C: Ankh, pgs. 74-), American Journal of Urology and Sexology, Volume 15:74-.
- McDonald, Andrew. (2018). “Influences of Egyptian Lotus Symbolism and Ritualistic Practices on Sacral Tree Worship in the Fertile Crescent from 1500 to 200 CE” (pg. 149), Religion, 9:140-.
- Mabry, Reggie. (2010). “Secret of the Ankh” (Ѻ), AfricaOnlineTV, Aug 15.
- Ankh – Hmolpedia 2020.