Main title return

Steps to reproduce

when doing a return at the end on the main title, it's not adding a line between the title and other paragraph under.

Expected result

introducing a new line right after the title or sending the cursor to the beginning of the next line

The ‘title’ at the top of the new V1 editor is the file name, not an H1 title. I think that’s what is showing in your screenshot.

Obsidian > Preferences > Appearance > Show inline title