Hi,
Here's a small list of personal tweaks applied after an upgrade from 18.04 Bionic to 20.04 Focal:
apt install kde-plasma-desktop
apt install plasma-nm
# Migrate networkd to NetworkManager in 5 steps
nano /etc/netplan/01-netcfg.yaml
netplan generate
netplan apply
systemctl daemon-reload
systemctl restart netplanXXX
# Disable/hide default virtual keyboard of vanilla SDDM
echo 'InputMethod=' >> /etc/sddm.conf
# reboot
# Disable/stop baloo_file
printf '\n[Basic Settings]\nIndexing-Enabled=false\n' >> .config/baloofilerc
# SDDM Theme : Sugar Candy :: Some minor tweaks
nano /usr/share/sddm/themes/sugar-candy/theme.conf.user
Hope you like it!