There is very little to destabilize in Belarus — Lukaschenko rules with an iron hand and most of the population, though they speak Russian not Belarussian (a resurrected language), don’t want to be under Moscow.
Yet, Putin doesn’t care what the people there want, or the people in Russia, or any other people. He cares about making the state of Russia a strong empire again and himself even more rich and powerful. Beyond that, he could be a KGB Colonel, a pseudo paladin of the Christian faith (under his strict control, of course), or any other charade to legitimize his rule and lust for power.
These moves could relate to the imminent demise of the Assad regime.