Armenians are christians, azeris are muslims(and ethnic turks). Turkey(Ottoman Empire) did a thing(genocide) on the armenians back in the day. Anyway eventually both countries were part of the USSR. The USSR collapses and all these new countries are created.

There is a large region in Azerbaijan, inhabited mostly by armenians(the azeris say the armenians ethnic cleansed the azeris from the region). This armenian controlled enclave in Azerbaijan is separated from Armenia. Wars ensue, things become as they are now, with many issues but relatively peaceful.

Fast forward to today, Azerbaijan has a lot of natural gas reserves, they are relatively somewhat rich and with the war in Ukraine, Russia(the ally of Armenia) refused to help Armenia and Europe has a huge appetite for non russian gas(ie for azeri gas). So Azerbaijan is in a very powerful political and economic position atm.

Azerbaijan is using that power to "solve the issue" by military conquering the armenian controlled enclave, knowing that Armenia doesnt have any military allies anymore(Russia refused to answer Armenia's equivalent to NATO's article 5 request for help) and Europe/West cant do much politically because they are extremely dependent on azeri gas.

Are the armenians the victim? Well, kinda. They are atm. But they were also the perpetrators in the past.