This is an interesting result. It also pretty much illustrates some of the folly of what we have been discussing. Before I mention a couple of considerations, let me reiterate my belief that you should do what makes you feel comfortable.

With that in mind, consider first that Tiffen filters, while they have been around for a very long time, are not a choice that routinely comes up when "good" filters are listed. I've not bought any of their offerings in recent years, so cannot speak personally about them, but that may be part of what is going on. Also...a number of filter purveyors offer a number of "grades" of filters. Bargain grade options usually present very different design and performance oarameters than come with premium products by the same provide.

Second, the 200-500mm lens is a specialty lens. Many parameters separate it from just about every other lens in your kit. Physical size, element size, construction type (perhaps), and optical grade (perhaps). Is it valid to generalize an observation made with this lens to all of your other equipment?

Third, your experiment is based on a quite extreme usage case for your 200-500mm lens at 500mm. I would be much more interested in results of a similar experment at a more typical subject distance...more like 100 feet, 300 feet, and infinity (or close), especially before making a general decision affecting usage of all my lenses.

As a photographer, I'm aware that we all need to make decisions about how we do the procedural parts of our craft. But as a scientist and particularly as an engineer I am convinced that we need to make those decisions in the most valid ways.

When I take a pic, I own it. Copyright law says its mine. To further prove its mine i put the C symbol and my name on the pic. To further prove ownership I can record it with the copyright office.
A few years ago, a guy took a copyrighted image. Then made changes to the image and claimed it as his own.
It went to court and the original owner lost , the court said it was a new image once edited.
Now look at the image with this message.
It is an AI created image. Copyright law is still being written I believe for these AI images.
so I took the original image, I made a few changes, and by the case mentioned above I should be able to claim it as my image and copyright it.
Whats your thoughts?