When using the app switcher on my S20, my most recently used app will often appear frozen as a mini version, but completely unusable. You can even interact through it. How can I solve this? I'm running the most recent security patch on Android 10. I've tried different launchers, including the stock Samsung Home and no difference.
As a first step can you close down all your open apps in your multi task and then soft reboot by turning the phone Off and On.
If it continues then place the phone in Safe Mode which disables downloaded apps but leaves the stock ones working and then see what happens. If it stops then one or more of your downloaded apps are possibly causing this.
Come out of Safe Mode and start deleting your most recent apps one at a time until it stops.
I wish you all the best with this situation.
Current Phone ~
Samsung Note 20 Ultra 5G SM-N9860_256Gb SnapDragon 865+
Samsung One Ui 3.1/ Android 11.