The work is what gets you to submission. The work is important, even if you’re sick of it. The work matters. The work is a significant and original contribution to your field. The work didn’t just come from nowhere.
You did it.
When you submit, keep at it. Your focus changes but you’re not done. You have to check the work. You have to make sure you understand the work, and can explain the work. You have to defend the work. You can do all of this because it uses skills you already have.
Use what you know, use what you can do, and keep doing the work.