I read that Kherson is the only land west of the Dnipro that Russia controls, and that it was more strategically important than Severodonetsk, such that they were willing to "trade" them. They suggested Putin cared more about the headlines than the tactics.
Edit: from the ISW
"Moscow’s concentration on seizing Severodonetsk and Donbas generally continues to create vulnerabilities for Russia in Ukraine’s vital Kherson Oblast, where Ukrainian counter-offensives continue. Kherson is critical terrain because it is the only area of Ukraine in which Russian forces hold ground on the west bank of the Dnipro River. If Russia is able to retain a strong lodgment in Kherson when fighting stops it will be in a very strong position from which to launch a future invasion. If Ukraine regains Kherson, on the other hand, Ukraine will be in a much stronger position to defend itself against future Russian attack. This strategic calculus should in principle lead Russia to allocate sufficient combat power to hold Kherson. But Russian President Vladimir Putin has chosen instead to concentrate all the forces and resources that can be scraped together in a desperate and bloody push to seize areas of eastern Ukraine that will give him largely symbolic gains. Continuing successful Ukrainian counter-offensives in Kherson indicate that Ukraine’s commanders recognize these realities and are taking advantage of the vulnerabilities that Putin’s decisions have created.
The Ukrainian leadership has apparently wisely avoided matching Putin’s mistaken prioritization. Kyiv could have committed more reserves and resources to the defense of Severodonetsk, and its failure to do so has drawn criticism.[1] Ukrainian forces are now apparently withdrawing from Severodonetsk rather than fighting to the end—a factor that has allowed the Russians to move into the city relatively rapidly after beginning their full-scale assault.[2] Both the decision to avoid committing more resources to saving Severodonetsk and the decision to withdraw from it were strategically sound, however painful. Ukraine must husband its more limited resources and focus on regaining critical terrain rather than on defending ground whose control will not determine the outcome of the war or the conditions for the renewal of war."
https://www.understandingwar.org/backgrounder/russian-offensive-campaign-assessment-may-31