You can restrict the call time to your preference by downloading additional apps.
Setting call time limit on Xiaomi Redmi Note 5A Prime is as follows:
Step 1: Go to CHPlay to download the Call Timer app.
.jpg)
Step 2: Select and activate the feature.
.jpg)
Step 3: Adjust the desired time.
.jpg)
With that, your setup process is complete. Best of luck!