> Higher sea level is not a problem, it gives more water to create lakes and fill aquifers in places like Sahara, Iran, and central Asia.
Higher sea level is absolutely a problem, as it disproportionately takes away the most valuable, economically productive, and inhabited land, and causes huge refugee crises. There's no shortage of seawater. Everything you mentioned could be done now (if we had enough power for desalination anyway). Higher sea levels don't make it appreciably easier, but they sure make everything else way worse.