After entering a title, how to keep it from becoming the first line of the spreadsheet, which affects the size of the columns.
There is no property ‘Title’ for a sheet. You may define different page styles (1 per sheet e.g.) and define a Header / Footer for each one. You may print the header and think of it as a ‘Title’ if you want.
There is in addition the sheet’s name. You may choose the name in a way to represent a ‘Title’. There are also fields similar to those used in ‘Writer’. One of the fileds you may also insert into the header (It eben is there by default.) is referencing the sheet name. probably this is what you want.
Edit ‘Header’ and ‘Footer’ of the page styles and try the settings.
What you type into a cell is simply content.