Seeking advice for best repair practice on older metal roof panels

Situation is low pitched metal roof - partially standing seam, and partially flat panels that seem to have been welded or perhaps soldered. This very old roof has had some manner of repairs done to multiple spots. The repairs appear to be asphalt roof cement applied over rusted areas. The entire roof was then painted. When I remove these patches, which btw is extremely easy to peel off, I discover rust, occasional serious metal degradation, and occasional holes all the way through the metal.
My question is simply this: what is the best practice to repair and maintain this roof? The plan is to remove all the patches, scrape clean all the rust, prime the bare metal, install a peel & stick product as a new patch, and repaint the entire roof surface.
Thoughts or suggestions are deeply appreciated.

How about some pictures?

While I am all about preserving the historical look and materials where appropriate, this might be a situation where you will spend more money and time fixing a roof that is due for removal.