you could try using a single entity and adding the mushroom attribute(s) …
type: custom:timer-bar-card
entity: sensor.waschmaschine_washer_machine_state
name: Waschmaschine
waiting_state: Stop
active_state: run
icon: mdi:washing-machine-off
active_icon: mdi:washing-machine
end_time:
entity: sensor.waschmaschine_washer_completion_time
text_width: 4em
bar_width: calc(70% - 10em)
mushroom:
layout: horizontal
color: "#dd6733"