Can you boot while holding down cmd (⌘) + V? This will put all sorts of text on your screen while booting, and give much more info to you (and us). If you could post a picture of that, with at least the last ~5 lines clearly readable, that would probably help.
If you are sure it’s because of a disk space issue there are a few things you could try. Just from the top of my head:
If you have an external disk you could install macOS on that, boot from it, and delete some files from your Mac HD that way.
Maybe you can still boot into safe mode (hold down shift (⇧) while booting) and delete files from there.
Boot into single user mode (hold down cmd (⌘) + S while booting) and use a command line interface
But some info from a boot using cmd (⌘) + V would really help a lot.