This is more important than people here seem to realize. Appearances are important on the international stage, and people don't always know what to believe

The more fault they can assign to Ukraine for various acts, the more Russia can legitimise continued hostilities against Ukraine. As an example, if a narrative that terrorist acts against Russia by Ukraine based organisations (or Ukraine itself) is accepted by the global community, that would give Russia a legitimate callus belli against Ukraine as Russia would have an interest in stopping these acts. Russia could then - legitimately- impose prolonged martial law in captured areas even after the invasion is concluded, provoke and synthesize further attacks to perpetuate the narrative and callus belli, and use it as justification to place pressure on other countries saying that the scoia'tael terrorists have moved operations to bordering regions. Meanwhile these countries wouldn't want to be the direct target of the Russian "anti" terror campaign. Local powers that don't comply are obviously hiding something and some such. It would be like what the us has been doing for decades but with an expansionist motive rather than an economic one. If the attacks on Russia were to somehow involve citizens of other countries, it would only serve to strengthen the cohesion by way of shared losses between the two populations and Russia may then take the opportunity to supplant sections of the weaker power's investigative branch. In time, Russia and its allies would become Russia and its hegemony wherein Russia controls every aspect of controlled nations despite being theoritically separate

All the while Russia would be calling for international support to deal with extremists, which would be taken up by its unofficial vassals within the galactic international community. Once Ukraine is gone, should that happen, there would not be a very strong centralization for resistance against the Russian campaign. As long as Russia keeps up appearances and offer the benefit of a doubt that that their intentions are legitimate, they can claim that they are the unfair subject of anti Russian propaganda put out by nato making it out to be the belligerent dictatorship that it probably is. The average person in neighbouringish countries which is not in immediate threat of invasion would be unlikely to offer more than indifference towards the situation until it becomes undeniable that Russia will not stop. Currently Ukraine is the sole focus of resistance against Ukraine, so the centralization of resistance is relatively high. If Ukraine falls, this centralization will become low where Russia will remain unified. Further resistance would then be spread out over every area that Russia can then threaten. This is especially true with the us no longer a part of nato

Meanwhile within Russia's internal media which they have near unilateral control over, news of attacks can be easily framed to place the average citizen in a state of fear and demand total obedience to an even greater degree as "investigations" would be able to easily justify the arrest of literally anyone as being a collaborator for terrorists