Sm1smom
Super Moderator
As an alternative, share 2 links. One view only, the other editable. I'm presuming most people are making changes because they simply don't realize that doing so will impacts others, so making the default link "view only" will solve that, whilst still allowing you to have a separate (but still public) link for editing without needing people to specifically request access.
Considering users need to update their timeline on an ongoing basis, you're assuming I have the time to maintain two timeline spreadsheets for the same FY. What is wrong with having those who consider the spreadsheet a useful tool send in access request in order to update their own timeline?