Write a resignation letter saying you are unable to complete the task assigned to you with the resources and support the party can provide. Say that you need to step aside so someone more capable can take up the project. Try to lean into the personal failure aspect with an undertone of having not gotten enough support from the party. Say that you aren’t wanting to leave the party but you understand if they don’t need someone who was incapable of running a simple project.

Its passive aggressive as fuck but sometimes that’s the only way to deal with having your suggestions ignored.