I bought it as a DECT device for home use with a Greek menu, large memory capacity for contacts, and connected it to the FritzBox 5530 provided by Cosmote for 1Gbps connection. The connection was very easy, the screen is bright and readable, I easily set the menu to Greek, BUT it does not save contacts with Greek characters!! Then I saved my mobile number with Greek characters on the FritzBox and when I called home from my mobile, I saw asterisks instead of Greek letters on the device's screen. This surprised me, and referring to the Greek section of the user manual, I saw that in the example of contact storage, the names are written with Latin characters, a detail that I initially did not pay attention to. Contacting GIGASET (a German company based in Germany, i.e., in an EU country, with products distributed in an EU country and, as far as I know, should have products according to the language of the EU country in which they are sold), they replied that they will forward it to their programming department and will respond to me in due course. So, whoever wants (like me) to save their contacts in Greek should be careful.
13/6/23: I just received an email from the company stating that the device does not have the Greek alphabet and cannot be upgraded to have it. So, what the Romans said is true: caveat emptor (buyer beware).
At the first opportunity, I will change it to one that has Greek among other languages.
In conclusion, because I consider Greek necessary in all devices sold in Greece and in our era, it is very easy to input Greek characters into electronic devices: Only ONE asterisk.

I got it so that I can send SMS because it said you can send SMS, but you can neither send nor receive

It is too slow for its price. If you type a number and decide that you want to call after all, it still continues to take the numbers you have typed. There are much cheaper phones that are much faster than this.