Effectively speaking, Belarus is a de facto colony of Russia right now under Lukashenko's rule. It has been and it continues to be a staging ground for Russian forces. During the first phase of the war, they did invade from Belarus as well. They continue to carry out missile strikes from Belarus. The Russian planes and air force continue to attack Ukraine through Belarus, and Belarusian ammunition-deposed missiles and artillery shells, etc. are being basically transported and used by Russia in this war.
Perhaps the only silver lining is that, partly because of the resistance of the Belarusian people, Lukashenko could not enter the war in full force on the side of Russia knowing that there is huge resistance, a significant resistance, to such a clear, open intervention, but that does not necessarily mean that it will not happen in the future. Particularly if the Ukrainian counteroffensive in the south goes well, Russia might end up using the available strategic resources, particularly long-range missiles and others, in Belarus to threaten and attack Kyiv more, not necessarily with ground troops but with missiles and artillery shells and the air force. That might bring Belarus in to fight more, but we have to treat this and assume that Belarus, under Lukashenko, continues to pose a threat to European peace and stability.