Double-stick magnets for wall / ceiling mount
If I understand your objective clearly, you wish to attach a magnet to one surface using adhesive tape. You wish to attach a magnet to another surface using adhesive tape. You wish to have the magnets attract to secure those two surfaces.

I have used double-sided foam tape, cut to the shape of a rare-earth magnet, attached after cleaning the magnet surface with alcohol. The same double-sided foam tape and magnet assembly was then attached to, for example, a television remote control.

It is important to match poles when you create these pairs. In my example, the solo magnet was stuck to the headboard of a bed, to enable a consistent location for the remote control.

In your description you prefer to have non-permanent attachment. This can be accomplished with a specific product or its equivalent. The specific product is known as 3M Command adhesive. It is also double-sided adhesive, with a tab extending from the assembly. One can purchase these strips in refill form. When you wish to remove them, the item is held securely, while pulling the release tab. Doing so deforms the foam and the adhesive, releasing the bond from the wall or surface.

The double-sided adhesive I use is weatherproof, but can be removed by carefully slicing it with a sharp implement such as a razor blade or sharp knife and the residue removed with common adhesive removal liquid.

With respect to the magnets, select your favorite vendor (eBay, Amazon, etc) and use "rare earth magnet" or "neodymium magnet" and look through the options. Flat, bar, sphere, disc shapes abound of various thicknesses and dimensions.