The claim about “14,000 culturally Russian people being killed by the Ukro-nazi regime” is misleading and leaves out a lot of context. The 14,000 number actually comes from the total deaths during the Donbas conflict from 2014-2021 according to reports from the UN OHCHR and OSCE. Those reports say the deaths included Ukrainian soldiers, Russian backed separatists, and civilians on both sides, not just ethnic Russians killed by Ukraine.
Also the whole “Ukraine is a nazi regime” thing isnt really backed up by evidence. Reuters Fact Check and AP Fact Check both reported there was no evidence Ukraine was committing genocide against Russian speakers before Russia invaded in 2022. Ukraine is also a democratic country and its president Zelenskyy is Jewish which doesnt really support the nazi claim either.
The self-determination part is partly true because the UN does recognize self determination in international law but countries also have territorial rights. The UN General Assembly did not recognize the votes in Crimea and separatist regions as legitimate and most countries didn't either.