With regard to digital accessibility, the Federal Monitoring Agency for Accessibility of Information Technology ("?berwachungsstelle des Bundes für Barrierefreiheit von Informationstechnik") recently published an update on gender-appropriate, digitally accessible language. The update from November 21, 2023 focuses on the semiotic level of gender signs and presents three basic principles of digital accessibility: barrier-free perception, comprehensibility and reproducibility. 
Accessible perception means that gender signs should be perceptible to all, regardless of impairments. This includes, for example, written language that is converted into haptic Braille characters or text that can be read by screen readers for blind people.
The comprehensibility of the signs is emphasized by pointing out that they must have a clear and coherent meaning and fit the context of the sentence. This is particularly important for people with learning disabilities or other people who have difficulty accessing written language. 
Finally, the importance of the reproducibility of characters is emphasized by recommending the use of characters that can be easily created by people with different impairments. 

The choice of gender signs should therefore always be guided by these three basic principles. In general, all common gender signs such as "*" or ":" can be barrier-free.
Thinking about gender equality and digital accessibility together is fundamental to ensuring that as many people as possible are included and that information is accessible to all readers.

The full report of the Federal Monitoring Agency for Accessibility of Information Technology can be found here (in German): ?berwachungsstelle des Bundes für Barrierefreiheit von Informationstechnik - Publikationen - Die digitale Barrierefreiheit auf der semiotischen Ebene der Genderzeichen (bfit-bund.de)
The download link for an accessible PDF version is here (in German): Digitale Barrierefreiheit auf der Ebene der Semiotik von Genderzeichen_barrierefreies PDF (bfit-bund.de)