I feel your frustrations, I spent most a day trying to figure out my solution. To do some troubleshooting, can you check two things?

1. Can you put a <div className={yourFont.className}>Test</div> in the _app.tsx to see if the font is loaded?

2. Can you check in chrome if the CSS variable is set correctly?

If both of them work, the culprit should be somewhere in the tailwind config.