Well it might be kind of tricky to pin down a time period with any certainty with these but I will give it a shot.

Looking at the figure's gear is the first obvious thing. His shield looks to be round, bronze, and has what appears to be a lambda on it which points to a Greek origin, made more likely in the Ptolemaic period than the Old Kingdom. In both he is wearing loose fitting trousers which are also more likely to have been found in later periods than earlier where they are not attested. If anything they indicate a Persian influence which would be better suited to a Ptolemaic time frame but Assassin's Creed is not always known for strictly keeping the protagonist's wardrobe accurate so this may have been chosen as a practical consideration over an Egyptian kilt. His weapons (looks like 2 spears) are too blurry for me to say anything.

Now the boats look more similar to Greek vessels to me in terms of rigging, the triangular sails and even the shields on the side, than of Egyptian barges.

Architecturally I really can not see enough detail to support any confident speculation, the structure he is standing in on the second image looks like it is constructed of large limestone blocks which unfortunately is what temples and monuments were constructed of from the Old Kingdom to the Roman period and the cobwebs imply that the structure is quite old. In the background of the watery image I think I can see a villa resembling Graeco-Roman styles with a sloping tiled roof but it is both mostly obscured and hard to make out.

All in all it looks closer to Hellenistic or Roman Egypt than the Old Kingdom to me, but it is entirely possible that protagonist could be a Greek in Egypt and the reason his gear and the vessel looks Grecian is because this is in Naukratis, a 6th Century Greek city founded in Egypt by the Pharaoh (Psamtik or Amasis) for the purposes of Mediterranean trade. We know that Greek seafaring vessels were indeed able to travel up the Nile river thanks to archaeological finds in the area, and beyond literary evidence we have coins, amphorae (broken pottery vessels), and other goods indicating widespread trade.

To be perfectly honest if you showed me this image unconnected to the rumors of an Assassin's Creed set in ancient Egypt I would not necessarily assume that was the case. Even if you showed me an image with an on-screen title stating that it takes place in Egypt and the protagonist were clad in standard Greek armour I could not definitely tell you (well, maybe by the armour).

Edit:

Please bear with me because I am trying to do this on my phone which sometimes hates me.

I want to find more connections in this but to be honest AC's standard for accuracy and/or the questionable authenticity of the images makes it hard. The lambda is a Greek symbol but it is kind of weird for an Assassin to use it, it looks like he might be wearing some kind of leather armour but not any kind I recognise from the should pads (but maybe that is not even armour?)

I also noticed that he is wearing leather sandals in one if not both of the images that look fairly typical for the Greek period but at the same time....they had sandals in Egypt and maybe he just came from Greece, idk. Khenut has also been pointed out by other users as the name of an Old Kingdom queen but given the continuity in Egyptian naming conventions between the nobility and common people and in naming conventions over time so this is not conclusive either.