I am not a real linux guru, but I force myself to work on Linux at least once day a week.
To work I chosen Kubuntu because it's an easy to use Linux distro.
A few weeks ago, Kubuntu 19.04 is arrived with some new features and applications.
One of these is the new interface based on Plasma 5.15.
There are many ways to update Kubuntu from 18.04 to 19.04.
For my Surface Book 2, I chosen the command line tool.
Kubuntu (and others Linux distros) are not optimized for the Microsoft Surface Laptops hardware.
I have a Surface Book 2 as main pc and I have the same problem.
But, thanks to the opensource projects, you can install a compatible kernel for these kind of laptops.
You can follow the instructions on this link and install the latest version to obtain the best performance on your machine.
First of all you have to update all installed applications on your installation with this command (it requires a reboot):
sudo apt update && sudo apt dist-upgrade
Check if your Update Manager is installed with this command:
sudo apt install update-manager-core
Open /etc/update-manager/release-upgrades in your favorite text editor and change the last line with this: Prompt=normal
In alternative, you can you nano with this command:
sudo nano /etc/update-manager/release-upgrades
Now you can do the upgrade to 19.04 with this command:
Note: If your current version is 18.04, you have to launch this command two times, the first one to get the 18.10 version and the second one to get the latest version 19.04