Jeremy is fairly trauma-free right now, apart from the inherent trauma of aging thirteen years in the literal blink of an eye, and finding out that the whole world he knew is gone, and that he has to kill monsters or he'll turn into a literal NPC.
Miranda, though? Hoo, boy, Miranda. The last thing she did before the Remaking was to tell Jeremy she hated him. She spent the next four years convinced she'd never see him again, and he was most likely an NPC, so he may as well have been dead two times over. The loneliness and guilt ate away at her, so she became a Thief and used elaborate heists as a way to distract herself from her darker thoughts.
Eventually she ended up (spoilers for things that won't be revealed for at least two more books) joining a party called the Sable Troupe that made their XP by robbing and scamming NPCs. No guilt, literally the only reason the System gives NPCs money is so it can be taken from them. She gets to be really close friends with everyone in the party, especially their leader, Sebastian--and maybe a little more than friends.
But then, just as she's starting to think she could be content with this new life, who does she just so happen to come across, but Jeremy! She immediately wants to wake him up as a Hero like herself and the rest of the Troupe. But Sebastian doesn't want the competition for Miranda's affection, so he uses a mind control spell to try and get Jeremy to kill himself. Miranda finds out, saves Jeremy, and kills Sebastian, giving herself some serious mental scarring. She also leaves Jeremy as an NPC because she knows she wouldn't be able to protect him if he got woken up, aka Big Trauma #2.
After that, she abandoned the Troupe and resorted to nonstop thrill-seeking to bury her guilt, usually in the form of even more heists. They kept getting more and more dangerous until she realized that these were actually suicide attempts, and she had nobody to intervene. The only reason she wasn't dead was because she was such an amazing thief that even when the heist should have been impossible, she would manage to pull it off.
A few months later, she runs into Aaron, another Hero who's trying to join the Underwing guild, who allow their members to awaken one NPC thst they'll take care of as a noncombatant guild member, but only if they do 100 dungeon runs. Miranda joins as well in the hopes of finally being able to wake Jeremy up and provide a safe-ish life for him. She ends up getting partied with Aaron and another Hero named Derrick, and that's how she spends the next nine years.
Fast forward to the beginning of the first book, and Miranda's party is about to run a high level dungeon just outside the city where NPC-Jeremy lives. Miranda goes to see him and accidentally ends up hiring him as an NPC companion. He follows them into the dungeon and gets awoken as a Hero, but in the process the party's rookie gets killed. Miranda's party is pissed and kicks her from the group, destroying the only positive relationships she had and leaving her thinking that she traded a kid's life for her boyfriend's, hitting her with the trauma hammer a third time--and this one's fresh and piping hot from the trauma oven!
And that's not even getting into her crippling fear of abandonment, her imposter syndrome, her lingering adrenaline addiction, or the fact that even thinking about Sebastian or the Sable Troupe we will cause her to have an instant emotional meltdown.
So yeah, she's got her share of wrenches in her gears.