That's a cheap way to justify Loki acting nothing like himself.
Viewing what happens over the span of maybe 2 hours (maybe) = / = experiencing years of this and maturing from them.
I can understand Loki changing a bit from seeing where his actions will take him, but he's a completely different guy here. You don't change that quickly.
Thing is, Loki is driven by his ambition, always has always will be. He changed tactics and personalities depending on the situation he is in
Loki we know in MCU post Avengers still wanted to rule Asgard and so on. Even in Thor Dark World he was a bit of a cunt although working with Thor. Then we see him going from wanting to kill and torment Odin to putting him in Norway and from there on it is Ragnarok.
Enter Loki from this timeline. As much as he is same Loki - he isn't. This Loki never got to post Battle of New York events, he right now is under supervision of others and as such must adapt to the situation at hand. Loki didn't change per see as much as he is playing the game according to the rules at hand. That's Loki.
I can bet you that down the line in Loki series we will see Loki take control of the events and do his own thing, but right now he needs to play be the rules of the game in order to win