Fully agreed. That campaign was much too limited in scope to really be effective. If the goal was to destroy Ukraine economically, just hitting grain silos at dockyards is far from effective enough. It could possibly have been a ploy to drive up global grain prices, of which Russia is also an exporter, but even with that, it hardly seems like the best choice for such expensive munitions, not when you can hit higher value targets like electric distribution or factories.
It also didn't have any long term effect. The grain ships are flowing in and out of Ukraine as Ukraine has destroyed the Black Sea Fleet's ability to control the Black Sea and the constant images of civilian infrastructure exploding convinced Ukraine's allies to deliver more AA.
Population
Again, fully agreed. And to add to it, Ukraine has a fairly large population. They are currently only conscripting people starting at age 25. Bombing shopping centers is unlikely to kill near enough Ukrainian civilians to matter for Russia. However, it does put political pressure on Ukraine's allies to send more weapons and, specifically right now, allow the use of donated weapons on targets inside Russia. If that comes to pass, such efforts will be a huge net negative for Russia.