You are about to close the project, you must do this with full focus to understand and document lessons learned for the entire project.
In the scrum terminology, this is called a retrospective. You can invite additional stakeholders to the retrospective to look at the project seriously. Once the project retrospective is completed, you can now start the final closeout for the project.
You have reached this point in the project based on the condition that all the required features have been implemented.
As you have spent your time and funds on the project, you'll have a few extra things to consider before closing down the project. You need to look into the backlog list and work with the business to get the importance of the remaining features. In addition, you'll need to find out if there were new features the business would like to have implemented.
If the set of backlog features are important and there are additional new features to be considered, it's possible a new project is warranted if the funds can be acquired. If the backlog contains lower priority features, it is likely a new project will not be initiated.
In this situation, the backlog needs to be transitioned to someone who can implement those changes. Another approach the business may want to take is, let's wait and see. If the backlog is important but they don't have a lot of new features at this time the business may want to wait several months to determine if new features surface and a new project is warranted. Regardless, it's very important for the backlog list to be given back to the business so they can maintain the list until future decisions are made.
You can focus on the overall effectiveness of the project, versus all the details that occurred since the beginning of the project, and can reflect on the improvements you have made, as individuals, and for the business.