As a paying customer, I wasn't expecting this so thank you! Can you expand more on your gut feeling? Also, I have different security expectations on Linux vs MacOS. Would you ever consider open sourcing the daemon?
The iCloud enabled MacBook is the one leaking memory. I'm leaning towards a hardware issue because the iCloud setup is the OS default and the number of reported issues is still low.
Edit: A recent reddit thread may have correctly identified the WindowServer leak being related to the amount of full screen video played. My impacted MacBook is often used for Netflix/Hulu content. https://www.reddit.com/r/apple/comments/qos5n5/memory_leaks_...
I'm also experiencing this on 1 of 2 M1 MacBook Pro Max 32GB machines. I've performed a full wipe/restore on the faulty MacBook and the issue persists. WindowsServer is usually the faulty process consuming 20+ GB of RAM. The only difference between machines is one uses icloud and the other doesn't.
Given the similarities between both machines and application usage, I can't help but suspect some type of hardware issue is plaguing a percentage of machines out there.