Head cannon for why Loki's face shape changes so much from the first Thor to the end of season 2 of the Loki TV show when it's been canonically not that long and he's already at least a thousand years old:
Well Loki was born a boy she was more often than not a girl as a child when she was closer to and wanted to be more like Frigga. Then, as Loki grew up and was more influenced by Thor and Odin and everyone else wanting to be a warrior, Loki reluctantly started shapeshifting into a boy more often. But since he was more inclined to be like Frigga he'd be uncomfortable and subtly alter himself to a more androgenous look that's closer to how he felt. He thinned his jaw, grew long curly hair, and gave himself a muscled but svelt look.
And as much as he liked the look - and as much as he adored his brother back then - Thor, in that thoughtless cruel way that even Asgardians can have, would poke fun with painful jokes that pricked the back of his eyes and sent him crying to his mother's strong, sheltering, loving embrace more than once.
Still, Loki is still more inclined to quietly rebel against Odin and it becomes a favored form.
But then, after he sees how fruitless it was in the Sacred Timeline, when he sees how they still lost and died painfully and Odin never acknowledged them for who they were to his end, Loki just...stops caring so much about rebelling against the closest thing they'd had to a father figure.
He's so tired.
Loki keeps his male persona up in the TVA, feels the smallest bit more protected, and has that slight advantage of sexism in all its forms even in as peculiar a place as Mobius' side. It helps that Mobius seems enamored with the more masculine parts of his current form. At first, when he's still terrified for his life, he's tense, nerves screaming as Mobius places a hand so high on his shoulder, that his fingertips slip beneath the ring around his neck.
Later Loki finds himself softening, sliding between the wary "he" that he'd become before becoming a Variant and the more amorphous self he'd enjoyed as a child, learning seidr at his mother's knee. Something about the easy touches Mobius gives reminds him of his less frictious childhood. Soothing.
And when Loki meets Sylvie, a less lucky Variant who managed to stay true to her self, changing fluidly between she and they (and sometimes him) but always keeping a face that reminds him of Frigga, he feels like he can try it himself. It's more than unsettling to walk down the hallways of the TVA in a shape, any shape other than the one known as Variant L1230 and she's ready to bolt as her face rounds, her body shrinks and curves, hair lightening closer to the shadowed strawberry gold she'd preferred when female. But she's still recognized, Casey grinning and pausing to tell her that he got a pet fish and they're really cool.
Oh. Right.
TVA.
Loki somehow forgot they don't look at the surface if they look at you at all. Her temporal aura is the same, regardless of the flesh that houses it.
And if that isn't the most effervescent, bubbling affirmation she's ever had.
An indeterminate amount of time later, as time is different in the TVA, Loki ends up chasing a Kang variant who's closing in on the formula to start the interdimensional war He Who Remains...remained to prevent. Loki is panting, chasing him, dashing madly between pedestrians in the crowd, losing to the Variant and -
He's bounding forward, faster than ever on all fours, leaping up onto the parked cars, pushing off with his hind legs, claws digging in and swiping, severing the tendons in the Variant's legs.
The metallic smell of blood is bright and heavy and heady and -
Mobius is sliding between him and his prey, crowding in towards Loki's snout, one hand reaching for his wet muzzle. "Hey, buddy," Mobius murmurs, smiling that signature easy, appreciative smile, crooked nose wrinkling a little. It doesn't reach his eyes. Loki isn't sure why Mobius seems so hesitant, but he pushes his head forward anyway, accepting the touch with a slight rumble.
It feels nice.
When Mobius's hand slips off the back of Loki's skull, he nearly whines, scrabbling around to shove his head under those wonderfully scratchy nails again. When Mobius finds the best spot under his jaw, Loki melts into a loud, rumbling puddle, eyes sliding shut and head dropping into Mobius's hand.
Mobius grunts. "Damn, Loki, your head is heavier than an entire ten year old."
Loki flicks an ear and doesn't move.
As it turns out, unlike with Odin's exacting expectations in Asgard, Loki doesn't doesn't even have to be human to be accepted for who they are.
