I self host, and back up emails locally. Done this since 2011, not that difficult (I must donate to Postfix and Dovecot projects!). To fetch emails I use K9 mail on my mobile devices, and thunderbird anywhere else.
I live these rules for 30 years and never got rejected. You can do whatever you want, like go and use interview time to vent out your bad internal state, who knows- maybe you'll get better outcome.
From experience, people who can't hold their tongue and tell bad things about their past bosses or coworkers, will also tell bad things about you behind your back.
First rule of interviewing- NEVER say bad things about past employers (or anything else, always be positive). Second rule of interviewing- ALWAYS say good things about past employers, or say nothing. Unless you are specifically asked about employer you prefer not to talk about- then ALWAYS say only good things about them. You talking bad things about past employment means you will also talk bad things about people you try to join. And it also potentially can backfire if recruiter figures you was actually the problem.
IMHO, if you do have negativity in you it will leak out later and make your situation worse. Better treat the core problem- which is you not being able to leave past where it belongs- in the past.