Don't worry! It's only stuff...

Install
sudo apt install -y snapd

CLI
snap find
snap install

Configure proxy
sudo mkdir -p /etc/systemd/system/snapd.service.d/
echo -e '[Service]\nEnvironment="http_proxy=http://proxy.example.com:3128/"' | sudo tee /etc/systemd/system/snapd.service.d/http-proxy.conf
echo -e '[Service]\nEnvironment="https_proxy=http://proxy.example.com:3128/"' | sudo tee /etc/systemd/system/snapd.service.d/https-proxy.conf
sudo systemctl daemon-reload
sudo systemctl restart snapd

# debug proxy
systemctl show snapd | grep proxy

###############################3
# proxy test (broken?)
# cat /etc/environment
http_proxy="http://BENUTZER:PASSWORD@proxy.hostname.de:8080/"
https_proxy="http://BENUTZER:PASSWORD@proxy.hostname.de:8080/"

sudo systemctl edit snapd.service
[Service]
EnvironmentFile=/etc/environment

sudo systemctl daemon-reload
sudo systemctl restart snapd.service

Install applications
# Visual Studio Code
sudo snap install code --classic

# Spotify
sudo snap install spotify

# (Micro)Kubernetes
snap install microk8s --classic

Links
https://snapcraft.io/