The SMO started in 2022. In 2014, after the western-backed Euromaidan coup, Crimea was annexed but then there were multiple attempts to resolve things peacefully, called the Minsk Agreements, which Kiev broke both times. In 2014, Donetsk and Luhansk seceded from the new far-right led Ukraine, fastforward to 2022 after a decade of fighting and Russia agrees to go in and resolve things by force.
Since 2022, Russia has steadily been gaining more and more territory, and has nearly completely taken the four oblasts they declared as their targets for annexation. Ukraine has slowly but steadily been losing ground, and NATO has proven to be incapable of matching Russian industrial output. Russia isn't trying to do a Blitzkreig, they are going carefully to fully demillitarize Ukraine and prevent casualties on their own end. They have the industrial capacity to field a protracted war, so they are playing to their advantage.