You need an embassy visa for Turkmenistan if you have an Austrian passport
Visa options for Turkmenistan
Visitor visa
Travelers need a visa to visit Turkmenistan for Business or Tourism. A paper or embassy visa is the only visa available for travelers visiting Turkmenistan. The visa is typically a stamp or sticker added to the passport. Travelers must obtain this visa from a local embassy, consulate or visa center before traveling. Travelers can get a visa on arrival at the airport in Turkmenistan if they receive an invitation from the State Migration Service of Turkmenistan. However, travelers without a visa may encounter issues during check-in. The government of Turkmenistan recommends that travelers secure a visa from an embassy of Turkmenistan before traveling.
This is not offered by sherpa°.
Apply on the government site.