Something similar has happened to me (and I've been a victim of identity theft), though not via PayPal. Here's what I recommend.
Step 1. File a police report.
Step 2. Freeze all your credit bureau reports. That will prevent further mischief. If you need a loan you can unfreeze them for a day or a week or whatever you need to get your loan, and then slam them shut again. I've had my credit reports frozen for many years and have never had a problem unfreezing for a few days to get a loan.
Step 3. Submit the police report and all of your correspondence where PayPal acknowledged that the charges were fraudulent and unauthorized, and where PayPal acknowledged that you haven't actually used your account since 2016 directly to PayPal's fraud department.
If you don't have that in writing, provide your phone log with dates, times, and hopefully the names of representatives. In my case, I could not get a human to respond via email and so used my phone logs. It was absolutely effective.
In your submission, you must say that these charges were not yours, and that they need to remove them and also desist from dunning you for amounts they know to be fraudulent.
Step 4. Close your PayPal account. You do not need PayPal to exist in the world and do not want them to have access to your bank accounts. The fact that they have dithered for months and their fraud department has not rectified the situation is all the information you need.
If you are desperate to keep this account open then you could go through the whole process that our friends here on this board will recommend, up through the food chain, one at a time. That is an excellent way to go, but if I were you, I would cancel the account given the recent history and worries about future issues.
Step 5. If PayPal tries to ding your credit report, send the police report, your phone logs, PayPal's admissions, etc., to the credit bureaus disputing the negative information, and telling the credit bureaus to immediately remove the false information. The credit bureaus will either remove it or contact PayPal and they will likely remove it. If they don't, there are further avenues with the credit bureaus.
Sorry this is a bit wordy....I'm writing quickly before an appointment. Good luck!