Not sure why you would make a topic like this and say no spoilers..
In my opinion there are almost no likable characters in the series, I'm not sure if that is intended or if the writers are just fucking up. Most of the characters are super annoying with no redeeming qualities.
At the start of the series I might have answered this with Elliot but then something happens and he turns into a completely annoying fuckwit.
For purely shallow reasons Alice is a good answer, love her chest.
An actual answer though is Margo and Diaz.
Margo isn't all that likable but that is more by design than anything else, her character is a specific trope and is used well.
Diaz feels like the only real/relatable character. She is stuck in the middle of a bunch of completely unfair shit, and just trying to do her best despite having absolutely no hope of ever gaining control of her situation. She isn't annoying for the sake of being annoying nor does she ever really complain about her powers. Her story is always interesting and you constantly learn new things about her that completely change your view of her.