Pegasus, SS7 or something else?

My ex installed Pegasus on my iPhone or iCloud or both. He is a very skilled hacker who also works in a field where he has plenty of resources, but I didn’t find out about this until recently. Apparently, while we were married, he backed up my iCloud on his personal PC and at least 2 other device. I changed my phone number over 10 times since the beginning of the year and I bought numerous phones, yet he still finds out my number and hacks my phones. The first time I bought a new phone, I created a new appleID; with the second phone I created a new account. Within 2 weeks both iCloud accounts were hacked and the phones (both iPhone X) were disabled. The next 5 or 6 phones were burners, and they all got hacked, including a flip phone. My calls get hijacked most of the times, nobody can get ahold of me because my phones never ring, I can rarely access my mailbox, and when I do, it’s empty, even though I know I should have voicemail. After I found out that my AT&T account was constantly being accessed by someone else, I changed providers and the last phone I bought was a Pixel 2 that hasn’t worked properly since the first week. I contacted a private investigator who told me that my ex is using SS7 (Signalling System Nr.7) and that there is nothing he or anyone else can do to help me, and until he gets arrested not to use any phone if possibl, and to keep my converstations clean around it. He even hacked the computer in my car and used it to remotely open the trunk, windows, turn up the stereo etc. I contacted the police and his PC is beeing examined, but the forensics and the investigation is taking too long. Has anybody experience any of these? One of the associates at the Apple Store told me that he’s been seeing a lot of similar cases lately.