What is causing VIX periodicity on monthly chart ?

There is certain periodicity in VIX long term movements when zoomed out. Looks like it is oscillating around cca 20. Anybody has an idea what is the cause of it? Any clues are welcome.

Now, those 3 waves represent time spam of 3 decades, so this is clearly not meant for exact timing :D

There was the last top caused by Covid 2020 market crash, but although it's little messy, judging by the higher lows on the chart, there could be another spike possible to "the gold spot" over 40 before VIX will very slowly confirm its long term downtrend.

I may use it as one of several indicators hinting, when to unload my UVXY positions. Which I didn't "loaded" yet, because I hope for a sale price - UVXY under 11. Fundamentals will be very important, when the time comes.

Not a trading advice, just my fantasies.
Chart Patterns

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