I also watched the "Ring of Power" documentary. Some of it is very compelling, some of it is over-speculative propaganda.
Another tidbit to satisfy your theory from the wikipedia page on Caeserion:
"Caesarion was proclaimed a god, son of god and King of Kings"
In addition to his Greek name and nicknames, Caesarion also had a full set of royal names in the Egyptian language:
Iwapanetjer entynehem
Setepenptah
Irmaatenre
Sekhemankhamun
These are usually translated as:
"Heir of the God who saves"
"Chosen of Ptah"
"Carrying out the rule of Ra" or "Sun of Righteousness"
"Living Image of Amun"[6]
There is a book called Jesus - Last of the Pharoahs that dives into this very subject in great detail.