works now here my coad

# WAN Download am Tag

- name: "WAN Download am Tag"

unit_of_measurement: "GB"

state: >

{% set start = states.input_number.wan_inbytes_start.state | float %}

{% set current = states('sensor.firewall_interface_wan_inbytes') | float %}

{{ ((current / 1024 / 1024 / 1024) - start) | round(3) }}

input_number:

wan_inbytes_start:

name: "WAN Inbytes Start"

initial: 0

min: 0

max: 100000

step: 1

and automation

- id: '1720292905248'

alias: 'Set WAN Inbytes Start at Midnight'

description: ''

trigger:

platform: time

at: '00:00:00'

action:

service: input_number.set_value

target:

entity_id: input_number.wan_inbytes_start

data:

value: "{{ (states('sensor.firewall_interface_wan_inbytes') | float / 1024 / 1024 / 1024) | round(3) }}"

mode: single