Could you try updating to the latest node 20 LTS version? You’re currently on Node 20.9 according to the logs. After updating to Node 20.18 or higher please delete the npm cache directory again and then try again (Fonts Are not showing in build - #8 by marcel)
I just wanted to let you know that I’m trying to improve how the Unity plugin handles this error with npm cache. It should be available in the next alpha release for you to try.
Could you try updating to the latest alpha release if it fixes the issue for you?