Have a careful look at Scrivener. It's an old workhorse for professional writers creating complex manuscripts--including screenplays. Generally the writer uses Scrivener to create a document with character notes, plot, scenes, dialog, etc., and when finished the document is "compiled" by Scrivener. After that it is ready to be imported into Final Draft (Final Draft 8 format).
Scrivener isn't free but it's not that expensive given all it does (about $50). It's available for Windows 10 and MacOS, and both versions look and function identically.
Don't mean to shower blessings upon it--it's not perfect, and I don't work for the company.