Don't have any data to show you, just words from experience and checking this stuff on private projects.
What I've found is that CSS filters performance drops are most visible when you're using them in animations. It can really screw up the UX. And when using it just for initial display - on high-end PC-s you might not even see the difference, but it's certainly noticeable on mobile devices.
I have some data and its really not that bad!
Thank you ever so much Una :D
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