I see where you are coming from, but Subaru completely loses progress AND feels pain. He remembers when Rem killed him. He remembers his leg being cut off by Ram and then tortured by Rem. He remembers seeing his comrades die over and over. He doesn't suffer humiliation- he suffers mental annihilation.

SUbaru is not respected as a hero- it is made clear time and time again that many don't respect him. Kazuma has useless weirdos to help him, but at least he has someone to cry to and who care about him. Subaru crying to Rem about them leaving him was heartbreaking. And I will not give non-anime spoilers obviously- I will just say Arc 4 is worse than Arc 3, and Arc 6 makes Berserk look like friends arguing.

Kazuma gets some skills, Subaru remains a basic human- you are born with skills you can't get XP.

If you read the IF novels you can see him break in so many ways.

And food for though- imagine that your ability is to reset if you die. There are no suicide pills- and then you reset in a game. Basically before a hard boss fight with no equipment. He knows he will die, and he does, often in such brutal ways.

Kazuma suffers a lot, but there is never a guarantee he will again. Kazuma if he gets in some real deep shit- he can ask Eris to send him to Earth and abandon his allies, and she will, it was his decision to stay.