My primary backup plan is to use my X100F more and more if the weight of my Z5 becomes limiting and change my point of view. Few, if any, would know that I heavily cropped the above initial images made with the X100F and then increased the size of those to display these views.
Another option is to use the Olympus TG-6 and/or the Ricoh GR III cameras for photographing when out walking. I haven’t been using the TG-6 for a while but I am keeping it for certain photography, if needed. To reacquaint myself with it, I used it to make the following image of my Z5 camera.
Another example of using different focal length lenses and cameras is below. The first was made at 200mm focal length with the Z5. The second, was made with the e35mm lens in the X100F. They were both made through the window and they both were heavily cropped.