Question about Homelander by the time between the Canon Episode of Diabolical and Season 1

In Diabolical (The Canon Episode), we see Homelander's private personality at first as naive and well meaning., He genuinely wanted to be a hero, but was easily corrupted by Vought and Stillwell and after covering up the fuck up in his first mission he learned that it doesn't really matter.

In Season 1, even in private, we see his personality as less unhinged and unstable as his private personality in Seasons 2-4 - While he is cruel and manipulative, even in private and when the cameras are off he is pretty stable and only starts to go nuts when his image is slowly losing its hold on the public on Season 2+the whole situation with Ryan.

So my question is, do you think there was a time before Season 1 and after his first mission that Homelander was beyond saving? When do you think he evolved into a Monster? At what stage of his career?

And second question is, do you think Homelander's personality, even his private personality on Season 1 was an act and that he is just throwing away the facade ("I can finally be myself), or that as the Seasons progresses he is losing his sanity and becomes from the manipulative Monster in Season 1 to the unstable, unhinged Monster we see in Seasons 3-4?