How long after restart does it take for the problem to appear?
Does it happen all at once, or does it gradually get worse?
If you reboot to Safe Mode, does the problem appear or not?
Starting up your Mac in safe mode may help you diagnose problems with your Mac.
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I also suggest restarting without restoring all apps and windows. That is, restart to a minimal state: Finder only. Open apps one by one. Take note of when the problem appears.
When the "Memory" pane is showing in the video (last several seconds), the "Ports" column for WindowServer says it has over 5000 ports open. The text is too tiny for me to discern the exact number; it's at least 5700 or 6700. That number seems excessive to me.
I suggest running Activity Monitor immediately after restart, with the Memory pane visible, and sorted on the Ports column (click the col heading; click again to reverse sort). Take notes on what happens with the Ports count over time.
I suggest doing this both in Safe Mode and after a normal restart. Safe Mode won't run any startup items, so you'll have to launch it manually.