The concerns about Sputnik are geopolitical in nature (weakening the sanctions regime against Russia for its doings in Ukraine, and the persecution of Navalny), not sanitary ones.
Not entirely. Their politicians boasted about it being the world's first "registered" vaccine a month before its Phase III trial started, that was an own goal completely of their making. It was only months later where they were able to finish their Phase III trial with very good results, but a few weeks behind the two mRNA vaccines.
That said, the effectiveness of Sputnik V has been established to Western standards now, so the only reason for the EU to refuse it when it is in crying need for vaccines is political, not scientific or medical.
Here in my country PM claimed to never accept Sputnik. Wonder what will happen if EU confirms it :)
[1] https://www.handelszeitung.ch/unternehmen/schweizer-biopharm...