The first 4 or 5 chapters are a little rough because it tries to charater build and world build at the same time. The writing isn't great but it moves along quick enough to not really matter. Its a good twist on the isekai setting by adding a few tropes together and not making the new heroes...
Speaking from experience recovering from depression/burnout is a long process and isn't fixed by will power or self control. The issue is that you used all that stuff up dealing with the shit life threw at you.
Sleep as much as you can until you have a decent sleep buffer and reduce the amount...
Gotta say I really wonder how the hero stacks up against Cross's masters considering they were shown to out class even other S rank individuals in the first chapter. Like, can he put up a good fight or will they stomp him into the dirt like everyone else?
Oh man, that reveal in the LN was so painful. We'll never know how who was first or how many he saved because Touma suffered tuama induced amnesia multiple times. He's just a hero at his very core.