The cash is held “as hostage” mostly by EU countries. USA is trying to convince those EU countries to return the money to the Russia, with very little success.

They are kind of sanctioning the Russia, but all the new sanctions they are making are tacoed. There were sanctions against Lukoil, but they were revoked.
The Russia and USA are stalling. The Russia is doing it to bleed Ukraine dry, USA for some reasons that are inexplicable.

The war will end whenever USA or EU decide to give their full support to Ukraine. As long as that doesn’t happen, Ukrainians do not really have any other option than to continue fighting.