I get stuck on the same thing. I think what I’m going to try is:

Choose a visual style that is easy to create assets for, probably 2D, low resolution, etc, and then give myself limited time to produce every asset I need, like 5 minutes for each asset or something. I can polish them later if the game is ever finished. Slay the Spire comes to mind as a game that did this, before the official release there was a time where they were systematically working through the assets and updating a few at a time each update, it was an odd time because all the assets had different levels of quality, but in the end it worked out, and the lower quality assets didn’t stop the game from succeeding.