Check out the old Aesop's fable The North Wind and the Sun if you're not already familiar with it.
The point is that if you want someone to do something, threats are not the best way to make them do it. People in general do not like being coerced. They will do everything in their power to not acquiesce. They will complain about your bullying. It's not to say that your threats will not work - if your position is powerful enough the other side has no choice but to obey, it can work - but you can be sure the other side will be looking for ways to defy you, and only obey if they have no other option.
Russia is not at the point of "no other option". In fact, Russia is very far away from "no other option". Look for example at similar situations elsewhere: Trump threatened "maximum pressure" on Iran, which did not make Iran come scrambling back to rejoin the JCPOA, but instead made Iran enrich more uranium. Neither did international condemnation change the situation in Burma, North Korea, or Mali. Compared to these countries, Russia is even harder to intimidate, not just because its economy is bigger but also because it is capable of annihilating the EU if it wants to (with nuclear weapons). Granted it will be annihilated itself if it does this, but it can still take the EU down with it. This means the EU is not powerful enough to force Russia to obey.
If the EU were to issue such an ultimatum, it will only ever cause EU-Russia relations to worsen without actually causing the changes you are looking for. If as an EU leader, that is your aim, then sure, you can go ahead with threats and ultimatums. If on the other hand you are hoping for a working relationship with Russia, it will not be productive.