I'm with you!
Cassian Andor was the hardest character to like, and biggest surprise for me, everyone else although interesting, was closer to traditional easy to digest "hero", this guy made it hard, but it's his need to see it through with Jyn to the "ugly" end that pays off, and makes it beautiful.
.
Again when he takes out the jittery Rebel who is about to lose it, ....... it got very real!
This was not going to be a black and white world, or character.
Then on Jedah when he shot the guys blowing the Imperial tank scavenging the Kyber Crystals, I thought screw this guy.
When Jyn breaks him down, compares him to a storm trooper blindly taking orders doing his job, I was with her.
Then on second viewing, only then did I see the guy he shot was tossing a grenade that would have killed Jyn, she has no idea of this.
If he didn't "do his job" she'd be dead, ... he's been doing this since he was six?!
And it only escalates from there, as the bond between them grows, she actually uses his words, "Rebellions are built on hope", which she had looked on cynically, until it's all they have.
His final "welcome home" to her had me.
Chirrut was easy to love, Cassian was again, probably the most gray area complicated character, and is what really won me over to this film.
If Netflix picked up a miniseries telling further tales of Andor and K2, I'd be all over it!