No, it's more correct to say both Russia and Ukraine both violated USSR sovereignty and declared independence from USSR, on this matter they are both guilty.
DPR and LPR are both remaining historical problem that came out of this act of secession. Worth noting that the government websites of both DPR and LPR use the ".su" domain reserved for USSR. LPR in particular seems to have a very rosy view of the Soviet Union, just look at their coat of arm.
This situation isn't comparable to current situation with PRC vs ROC, or even any of the historical periods where China was split apart into several pieces. In all of those periods of disunity there's always at least 1 if not more faction who proclaim themselves to be the legitimate government of the Central Plain. There has never been a case where during a period of disunity there's no power left who claim to be the one legitimate government of China and in every case when a power finally takes out all the competition and unifies China that they declare themselves to be anything other than the ruler of the Central Plain, even in the two cases where the dynasty came from outside of China as soon as they are ascendant they declare themselves to be Chinese and rightful ruler of China, and they proclamation where acknowledged as valid by subsequent dynasty/government.
In order for there to be an equivalent situation as Russia/Ukraine both PRC and ROC will have to declare that China no longer exists and they each exist separately as People's Republic of Mainland and Republic of Taiwan. In the real word instead both side have kept the "C" in their name and insists on their sole legitimate government of all of China (ROC being pressured into maintaining this position). Then Kinmen's demilitarised zone thing can be a DPR/LPR situation.
