no, this does the trick, I just found it in another of my templates. Button-card is so horribly versatile, we can template almost anything!
duh, so silly, I keep forgetting this entity.entity_id:
custom_fields:
plot:
card:
type: custom:mini-graph-card
entities:
- >
[[[ return entity.entity_id; ]]]
button card template:
plot:
custom_fields:
plot:
card:
type: custom:mini-graph-card
entities:
- >
[[[ return entity.entity_id; ]]]
group: true
points_per_hour: 1
hour24: true
line_color: var(--primary-color)
line_width: 10
hours_to_show: 24
update_interval: 600
show:
name: false
icon: false
state: false
points: false
legend: false
average: false
extrema: false
labels: false
fill: false
labels_secondary: false
name_adaptive_color: false
icon_adaptive_color: false
styles:
custom_fields:
plot:
- position: absolute
- top: 55%
- left: 50%
- width: calc(100% + 25px)
- transform: translate(-50%, calc(-50% + 10px))
- z-index: 3
- --paper-card-background-color: 'rgba(0, 0, 0, 0.0)'
- --ha-card-background: rgba(0, 0, 0, 0.0)"
- --ha-card-box-shadow: 'none'
- pointer-events: none
button card config:
- type: custom:button-card
template:
- button_body
- plot
entity: sensor.cpu_temperature
name: Cpu temp
preview:
(noticed I have recorder disabled on a few of them 
)
thanks Petro, nice embellishment of the frontend today!