First, read the United Nations University Widner Technical Note 22/2021 "Ethnic conflict, tensions, and protests: Taking stock of available cross-country data" which provides an overview of available cross-country data on ethnic conflict, tensions, and protests. The report includes an analysis of 16 different data sources with selected descriptive analysis of indicators and comparisons among them. The Technical Note suggests that data on ethnic armed conflict is easily accessible, especially through the GROWup – Geographical Research on War, Unified Platform. Moreover, the updated version of the Minorities at Risk (MAR) and accompanying datasets will also provide useful data. However, the Note states, "...data on ethnic tensions, protests, and other types of violent and non-violent events (including the actors involved) is currently scattered across different sources, with differences in coverage and in the information provided."
ETH Zurich is a public research university in Zürich, Switzerland. Founded in 1854 with the stated mission to educate engineers and scientists. Their International Conflict Research (ICR) unit produces several relevant datasets found HERE. The ACD2EPR makes the linkage between conflict and ethnicity. EPR Core Dataset identifies all politically relevant ethnic groups and their level of access to state power for all countries of the world from 1946-2021. It is complemented by GeoEPR that adds geo-spatial information about each ethnic group.
You might find useful the Targeted Mass Killing dataset published by the School of Politics & International Relations of the Australian National University.
