I find that the to-do note and note are very similar. The only difference is to-do note can have an alarm.
Coming from Evernote, I can have alarm/reminder for any note. Every note is a note. If I created to-do in my note, it still a note with list of to-do. If I need to be reminded to read a note, I just set an alarm/reminder on it. Don't need to convert to do-no note.
I am still trying to grasp Joplin's concept of separating to-do note from a note. This is a bit unusual, even compare to other note app, OneNote, Notion, Nimbus, Standard Note etc.