idk if this will help anyone else but my mom always used a saying with me: Pick a Corner.
it was in relation to cleaning my room but as I got older it was an analogy used for any seemingly insurmountable task and coping with a lot with adhd and getting started. No matter what it is don't look at it as a whole, just pick a corner, start, don't worry about how much you get done or plan to get done. Just start.

You got this.