So I had the demand to access my network from anywhere to service my devices and appliences. Here wireguard came to the rescue, Wireguard is an open source VPN-like network extender which provides a highly secure end to end encrypted tunnel. As it is not very hungry on resources it is runing quite good in parrallel on the RaspberryPi 2 that runs Pihole.
A major prerequisite to all this is obviously a public ip address. As my internet provider only gives a dynamic ip which is also behind a carier-grade NAT, so can not be reached from the internet, my only way to be reachable is by paying €5/month extra for a fixed IP address. this is also the only monthly cost for all of my selfhosted things.