Inspecting your project, I see that the icons and some fonts are attempting to load from localhost. That strongly suggests some sort of build issue.
![JeffreyThompson2_0-1701706444636.png JeffreyThompson2_0-1701706444636.png](https://community.esri.com/t5/image/serverpage/image-id/87921i4142E6445100BB2C/image-size/medium?v=v2&px=400)
Even though these are not custom widgets, your problem may still be in your custom widget. Errors in a .json file can affect the build in strange and unpredictable ways. I was especially look for trailing commas. I had one trailing comma that broke not only the project I was working on, but also prevented me from creating a new one. Another common error that causes build problems are folders containing no files.
GIS Developer
City of Arlington, Texas