I changed phone from Gauguin to Vayu(Poco X3 Pro). Vayu has more kernels to use. And hasn't this issue.I have this problem with stock MIUI and I had it with PE as well. Sometimes it happens once a day and some 10. Noticed some apps can make it happen more frequently.
To make sure we are talking about the same issue, I am experiencing huge shuttering (~10 FPS), and this either goes away after a few seconds or untill I pull down the notification tray.
I actually talked about this issue many months ago.
If you found any solution please update us.