I am a critical resource and want to ask for project release.

I am critical resource of the project and most of the part depends on me. I am not good with project as it is non billable and the people as everyone is not doing their tasks properly and at the end those tasks coming to me with critical timelines. Now everyone in the project handover everything to me and they went to another project without completing their tasks properly. The lead simply said that he is not responsible for anything and I have to face it everything whether issues or escalations. Here my problem is the everything left on me and the times are very thin. I have said same to manager but no response from anyone. I want to ask for project release . To whom I can ask. If not I am ready to put my papers. But my concern is 90 days notice period. Not sure whether anyone getting calls for interview eventhough I am confident on my skill. Every suggestion is helpful to me. Thank you