Sherwin-Williams recommends Loxon X as best exterior cinder block paint. Im covering a 30 yo paint job that has held up well.

What is best long lasting paintable caulking tube sealant for block, wood, metal, plastic?

Do I need to scrap all these mortar seams? Most mortar seams are cracked like this and If I scrape like I did in the 3d pic, paint does scrape off. Here: https://imgur.com/a/iVTUXdP

I want this job to LAST!