If you cannot update to Android 10, you can still improve your Smart 4's speed by:

variant arrived with pre-installed, standard Smart 4 users may need to check for official Over-The-Air (OTA) updates or explore manual installation methods to access the features of Android 10. 1. Official OTA Update Method The safest and most straightforward way to update your Infinix Smart 4

Infinix never released Android 10 (Go edition or full version) for this model. The phone’s update support ended with security patches for Android 9 Go. Why?