Thanks for posting your question in the Apple Support Community. I understand that your Mac isn't turning all the way on.
Which part of the start up sequence is your Mac getting stuck at? Take a look through this article to see which steps to take based on which screen you're getting stuck on: About the screens you see when your Mac starts up
If none of the steps in the above article work, then I recommend to try starting up in macOS Recovery and see if you're able to verify and repair your disk and reinstall macOS. Here are the steps: About macOS Recovery