I think once the East and South get under control the Russian Railway Troops will move in and fix the railways sabotaged by the Ukrainians to move more equipment and supplies in.
Europe is sending all its obsolete trash weapons to Ukraine courtesy of the European Union which setup a fund for this.
They send obsolete weapons to Ukraine, that they would need to pay money to dispose of, and get cash in return. It is a steal really.
The logistics to actually deliver these weapons and their actual suitability for their defense? Not relevant. This "generous" EU support package is covered by the cynically named "European Peace Facility".