Well, I just tried clearing the IP tables and it made no difference at all. Just hoping for a momentary fix which might result in more ideas I had PIA disabled and shut off. Then I cleared the ip tables, waited a minute, tried using the Internet and nothing worked. Then I restarted PIA but left it inactive without use of the killswitch, same thing. Finally, as I have done 100+ times during the past couple of years I went ahead and enabled PIA ... voila, everything works as it should. It's absolutely maddening.
Time to take the dog out, will be back tomorrow. Have a great Saturday.

Better late than never.
Mark this solved then.

@business_kid: No, what are you talking about? Nothing has changed !!!
The problem is *NOT* that PIA won't work. The problem is that I can't get the machine to use the Internet without using PIA. It is not possible for me to delete, deactivate, or disable the kill switch. No matter what I do, without PIA enabled there is no Internet. I'm trying to figure a way to completely wipe out anything & everything PIA related on my machine so that I can begin using the Internet again without VPN services.

Looking over the thread, It seems the best way to proceed now that we finally get what your problem is is this:

1. Remove and purge PIA
2. Remove and purge Network Manager
3. Install network Manager
4. Reboot.

The worst that can go wrong is that you won't be able to access the internet, and that's an easier problem to solve.

.... not if you can't access the Internet for additional help to solve that new issue (missing NM). I might try these suggestions but first I'll see if I can find a network manager .deb file for manual offline installation since that would be the only way for me to get the network manager back at that point.

..... BTW, I did state exactly that right from the beginning of this post, and later on again.

Does the /etc/resolv.conf file change between enabled and disabled?

F**K, exactly what I was trying to avoid !!!

Took me about an hour to manually find anything and everything PIA related and delete that from my system. Then, to be smart about it, found myself the network manager .deb file for re-installation of the Network Manager once I removed that. Had to have it in advance of course, knowing that after a reboot there would be no more Internet access. Well, apparently when you remove the Network Manager (without using --purge) there are still some dependencies which get removed at the same time ..... dependencies which ARE NOT INCLUDED by default in the Network Manager .deb file.
Bottom line, due to the missing dependencies in the .deb file a working Network Manager could not actually be installed.

Then searched around on the Internet on another machine, seeking a manual installation without Internet access, but all of that was just hours more of wasted time.

Needless to say, eventually I gave up and did exactly that which I was trying to avoid altogether, by re-installing my system from scratch. I just absolutely hate & loathe doing that without planning weeks ahead because I always dread all of the custom settings and application configurations which have to be re-configured. Even by replacing new .config .local data with previously backed up .config and .local data, there is still considerable amounts of work to be done for home network access, backup drives access, application configurations which are not included in standard folders, and the printer setup for my lexmark color laser printer which is always a nightmare on MX Linux systems ... even with the Lexmark provided Linux drivers.
Finally got everything aside from the printer working again and I'm about to give up on the printer. What a colossal waste of time.

Moral of the story (for me anyway):
Do not under any circumstances for any reason remove the Network Manager !!!
If I hadn't done that, eventually it would have all been figured out one step at a time, as opposed to having to redo the entire system all at once.

NOT SOLVED ... just an incredibly frustrating experience.

I tried to get PIA to work in Slackware to no avail (this is not a call for help , yet), PIA keeps on trying to connect, i use top in the terminal, identify the pid, kill -9 **** , it is gone then i switch back to Ubuntu on the same machine where PIA works fine, wish PIA came out with a version for slack and compatible systems ( not knocking Slackware here). My two cents.

You can try the info. on their guides page for different Operating Systems:
https://helpdesk.privateinternetaccess.com/guides

Alternatively, if you have your own valid PIA account you can also try to get ahold of their tech support directly, to find out if there's a strictly terminal based installation possible? Let me know how it worked out?

Thank you LinWinux,i will post the results if successful

FINALLY ....

The latest PIA update to version 3.5.1 and also the one before that are working correctly! With MX Linux it is now possible to use the "kill switch" function to turn the VPN off, as well as turning it back on. Personally I believe that the issues which I was experiencing may have had something to do with the fact that the MX Linux developers had packages available in the package manager for PIA, NordVPN, ExpressVPN, and so on ... which may have conflicted if the user had those packages installed, in addition to following the standard installation routine by the developer of the actual VPN service.
I came to this conclusion because my wife and I both utilize the XFCE desktops, but she prefers Mint as opposed to MX. She never experienced the problems with PIA that I did. The only, to me, common denominator was the fact that while both machines had PIA installed as per PIA instructions, mine was the only machine that also had the MX Package Manager VPN files installed as well.
I believe that because of the MX files I was also not able to remove my PIA completely in order to attempt fixing the issue, or to just live without VPN altogether. So it's probably best to stay away from the package manager for VPN. Instead just follow the advice of the VPN vendor to make things work properly on your Linux.