I’ve see a few threads now looking for a solution to stop my Anki program window from flickering, most over the past few years and have been locked and left unanswered. I found a solution that resolves the issue entirely.
The issue is due to a conflict with my GPU’s driver (Some suggest it could be G-sync related, but turning VRR off actually made it worse for me).
While in Anki, go to (Tools → Preferences → Appearance → Video Driver) and set Video Driver from its default to Software. This will have Anki rendered by your CPU only since resolving GPU conflicts is not worth troubleshooting. Doing this stopped the flickering entirely for me and I hope everyone else as well.