Need help to optimize Date/Timestamp Operation - Change Weekday to different Language

Hello together,

i am new to the whole Home Assistant, but what should i say, its simply great!
Yesterday i tried to do the following:

I implemented an ICS Calendar which shows me the correct day of the gargabe collection and which type of garbage is collected on the correspondig day. Works good.

The next step was, to create a template sensor which works. But i dont know; I want to learn if there is a better way how to get the same result:

Startpoint is sensor.ics_1 which delivers a Timestamp in the following way: 2021-01-07 00:07:00+01:00
I want the weekday in German, so i build the following statement:

{% set day_array = ["Sonntag", "Montag", "Dienstag", "Mittwoch", "Donnerstag", "Freitag", "Samstag"] %}
{% set day = day_array[as_timestamp(state_attr('sensor.ics_1', 'start')) | timestamp_custom('%w', true) | int ] %}
{% set date = states('sensor.ics_1').split(',')[1] %}
{{ day + ',' + date}}

Output is now: Donnerstag, 07.01.2021

Is this a good way to do it? Or what can i optimize to get it faster / more readable / more solid.

The Sensor could also deliver a String in the format: Thursday, 07.01.2021
Then i need to replace the weekday in the String. But i am not sure if that would be better as to work with the timestamp?

Thank you