Can I switch a section off for a while without deleting it?

Yes. Hide it on every device:

1. Open the page in the builder: Content → All Pages, click the pencil (Edit) icon on the page, then Open Builder →.
2. Click the section to open its settings.
3. Tick Hide on all at the top of the panel.
4. Click Save.

A section hidden on all devices isn't sent to your store at all, but it stays in your Sections list with every setting and image kept. When the sale comes back, open it, untick Hide on all and Save again.

This works better than deleting the section, which you would then have to build again from scratch.