Thanks for the follow-up and update.
For Angular SPA (Single Page Application), you may need to redirect all queries to the index.html.
Use a startup command passing --spa
argument to PM2 as followed: pm2 serve /home/site/wwwroot/dist/angularfrontend --no-daemon --spa
or using a process file.
For more details, please check: Angular Deployment on App Service Linux
If the issue still persists, if it's fine, please share your WebApp name.