To prevent two words from being separated at the end of a line, hold down the Command keyCtrl key and the Shift key when you type a space between the words.
In Calc, you cannot insert non-breaking spaces.
An example of a non-breaking hyphen is a company name such as A-Z. Obviously you would not want A- to appear at the end of a line and Z at the beginning of the next line. To solve this problem, press Shift+CommandCtrl+ minus sign. In other words, hold down the Shift and CommandCtrl keys and press the minus key.
In order to enter longer dashes, you can find under Tools - AutoCorrect Options- Options the Replace dashes option. This option replaces one or two minus signs under certain conditions with an en-dash or an em-dash (see LibreOffice Help).
For additional replacements see the replacements table under Tools - AutoCorrect Options- Replace. Here you can, among other things, replace a shortcut automatically by a dash, even in another font.
To support automatic hyphenation by entering a soft hyphen inside a word yourself, use the keys CommandCtrl+minus sign. The word is separated at this position when it is at the end of the line, even if automatic hyphenation for this paragraph is switched off.