Being kicked out is not the reason of this guys edgy emo phase. Is that for a while it looked like they tried to kill him since she didn´t even have the "common sense" of checking the place before sending her very weak friend to the slaughterhouse nor even give some apologies after the deal.
Yes, we all need some reading comprehension
Oh, it's worse. Basically.
- He was sabotaged since day one by the lesbian Priest girl and the Knight guy. They ensured he would not receive any training, nor be taught anything. They in fact made sure he was so busy with various menial tasks and other stuff that he couldn't even do it on his own when he had time.
- They also made sure to trip him up and keep him out of fights so he'd fall back further and further. Because both of them have designs on Sasha and saw him as an obstacle to what they wanted and wanted him gone.
- The reason to kick him out becomes even LESS of a reason, when they begin recruiting low level/entirely new adventurers to build up Sacred and branch out. Sasha herself even notices that. When these same people begin to actually train newbies and teach them to fight. Something they never did for Hyce but very much did for her when they originally set out. She sees it, wonders about it, especially since they were the ones to convince her to kick him out, and then shrugs it off and moves on.
- Sending him over there was stupid, and shows she never thinks things through nor puts in even the most basic of effort into anything.
- Further when he collapsed and might've died, she left immediately on another quest. She didn't even stick around to wait for him to wake up or to see if he recovers much less apologizes to him. It makes sense for the other two people mentioned earlier, since they want Hyce gone. But not for her to do so.
- In the WN when she finds out those two people did all these things, are into her, how they sabotaged Hyce and confess to her. What do you think she does? Get angry? Kick them out? Feel bad? She does nothing. She keeps them around, they get to keep acting like they did before, lusting after her and treating Hyce badly.
- She also keeps getting recognition for shit Hyce did, as the world bends to make her out to be the bestest thing ever. Even the girls Hyce befriends, rescues, and works with somehow end up primarily working for Sasha's benefit in the end.
This isn't some great writing or deep plot. It's that the author completely fell in love with Sasha and ended up trying to bend the stories in various ways to make her out to be the bestest ever. Ignoring all her actions and fanboying her hard. Sasha is the authors waifu, his favourite character. And the manga seems to SPEEDRUN that.