No work visa needed
EAEU citizens: no work permit needed
Citizens of Eurasian Economic Union member states who work in Armenia are exempt from a work permit; they may get a certificate confirming legal residence.
Source: Migration and Citizenship Service of Armenia – Citizens of EAEU member states (migration.mia.gov.am).
What the source says
"Citizens of EAEU member states who work in the Republic of Armenia are exempt from acquiring a work permit in Armenia" … "The Member-States of the Eurasian Economic Union are the Republic of Armenia, the Republic of Belarus, the Republic of Kazakhstan, the Kyrgyz Republic and the Russian Federation." (https://eaeunion.org/?lang=en)