First make sure you have the latest BIOS version and CHIP Set installed from DELL: Support for Latitude E6440 | Drivers & downloads | Dell US
Latest DELL BIOS Version is A23 - 10/031/2018
Latest DELL Intel Chipset Device Software - 01/15/2019
Latest DELL Intel Management Engine - 02/27/2019
Latest DELL Intel Integrated VGA Driver - 04/19/2019
Basically I would update all of your DELL Drivers from DELL Support for your laptop.
Your HD 8690M DELL driver is from 2015. Try using AMD Generic Laptop driver from here: Radeon™ Software Adrenalin 2019 Edition 19.5.2 Release Notes | AMD .
Your Intel Integrated Graphics MUST be the latest version for the AMD Driver to work properly.
How to install AMD Graphics in a laptop: https://community.amd.com/thread/207699
Once you have updated all your Windows 10 Intel Drivers and BIOS including AMD Graphics Driver, then try to update to the latest Windows Version 1903 instead of version 1803.