There problem with DSL/pppoe in 18.04 flavors:
DSL/pppoe connection doesn’t work: I create it, but instead of it autoethernet appear.
BUT! Somehow there no such problem in Kubuntu.
I just tried Ubuntu Mate and there AutoEtherent appears instead of what I’ve created.
But there was pppoeconf. Strnge: UM has it, usual Ubuntu has it, but not in Xubuntu.