Hey Ismael,
thank you for your reply.
Of course, you can also disable the cookie function in Matomo. However, this means you won’t have any data on returning visitors. I have now solved this by using the Matomo cookie as an additional custom cookie. This works as desired. If consent is given, the Matomo cookie is set; if consent is refused, cookieless tracking is used.
However, this is not exactly easy for laypeople to implement.
I would argue that a theme should definitely support Matomo natively these days.
Thank you very much, the problem has been solved for me.

Hello Ismael,
yes, I also thought this was the right way to store the translation. But unfortunately it doesn’t work that way. Please try it yourself on your own test installation. For me, the translation only works if I change the text directly in the PHP file (class-form-generator.php).
Nothing changes for me via the .po file. I have changed the code on line 13620 – 13622 in :

#: framework/php/class-form-generator.php:257
msgid "Found errors in the following field(s):"
msgstr "Fehler wurden in folgenden Feld(ern) gefunden:"

Unfortunately without success!
Perhaps the error is elsewhere.
Best regards
LoMoe