They already won. They defended their independence and still form a buffer zone between Russia and NATO. You have to be delusional to believe that Russia is still able to take Kiev. Worst case (for Ukraine) Russia will take over the territories they held before the invasion started. It’s still a disaster for Russia and a huge win for Ukraine.
The entire Ireland is in the EU already. Northern Ireland can access the single market without checks. The checks are between Ireland and GB.