Nokia Suite 3.8 - Do I have to update all maps and voice guidance files on my phone even though I don't need them all anymore?

You can leave out the ones you no longer need. When the update is ongoing, the old versions of your maps and voice guidance files are deleted first. In the next view after the deletion, you can choose which items you don't want to transfer to your phone anymore. To leave out maps you don't need, click the X symbol next to each of the queued files.