It's NOT always on the person if their phone was jailbroken.
If a phone was jailbroken behind your back by someone like a disgruntled abusive ex, who had already been sneaking into your computer and phone and cloud for years before the breakup, and then they gave access to all that info to whoever they wanted, including any rando online, basically doxxing, where would you begin to correct it and the resulting tech/device problems? When you can't afford to buy a 3rd new phone. When you realize this happened for years after you left the ex and never knew someone was piggybacking on your cloud/device until people got bored and blew it all up.
Even when factory resetting multiple times and making multiple new Apple ID's with a "from scratch" setup (no restore from backup, completely fresh ID and no cloud enabled etc) yet it still doesn't work.
When one has pretty much deleted their entire online presence with the exception of major necessities like bill-payments and grocery orders and health stuff like telehealth. No social media, one real email with one backup email and a few decoys just in case.
Harrasment can't be proven when it's all centered around private personal info being sent to people like family and friends and neighbors and employers and landlords. When people are angry and believe you openly shared their private info but you didn't share their personal info with anyone except maybe in therapy, which has been via telehealth since lockdown on devices that were accessible to your ex before you split.
The only proof is the suddenly hostile/weird attitudes of everyone around you, people who suddenly start to talk about deeply private info they shouldn't know, and it can barely even be reported to IC3 or the cops except to say your prior emails were all hacked and all the contents emptied.
That your iCloud was accessed and completely deleted and in the old data's place were crazy photos to corroborate all the racist social media posts that were made while you thought your account was deactivated or when you were sleeping.
When your cloud had been set to sync WhatsApp and notes you made for therapy and which you thought were set to only save to your phone and then those notes got accessed, copied, and edited to say even more crazy stuff so when you first realized what was going on a reformatted and redownloaded the compromised cloud, all that ended up on your phone were insane photos and crazily edited notes while the original photos and notes and everything else is just gone.
What would you suggest then? Except trying to read logs and trying to become a programmer/hacker/apple device expert. While also trying to chase down any proof that your new device and ID are still screwed up and no matter how many new emails and IDs and WiFi passwords and docsis routers you buy, someone is still tracking you and sending damaging lies about you to anyone new you might meet and messing with your ability to even find a lawyer or tech expert to help sort it all out. When every web page you visit is broken or full of garbage. When your eSIM deletes itself on a regular basis and sometimes becomes a business line and sometimes duplicates itself in the second eSIM slot and sometimes disappears for over a month and you have to get a tracfone and have to change everything to paper mail and these days less and less places are even offering paper mail and if you're disabled social security won't let you use paper mail for your payment for more than 3 months before they cut you off for not setting up direct deposit.