Ukraine operations in the Crimea front

 ISW:

...

Ukrainian strikes on Russian military assets in Crimea often generate Russian panic disproportionate to their kinetic effect and negatively impact Russian morale. Ukrainian strikes on Russian rear areas consistently cause panic in the Russian information space and generate frustration and criticism about the Russian military command.[26] Ukrainian strikes on Crimea have also caused some Russian milbloggers to panic and erroneously perceive any Ukrainian actions targeting Crimea as conditions setting for imminent Ukrainian operations to liberate the peninsula.[27] Russian milbloggers notably expressed concern that Ukrainian forces were able to operate a drone and record footage of a strike on a Russian S-400 air defense system in Crimea about 120km behind the current frontline.[28] The Russian withdrawal of aviation elements and other military equipment from the Chornobaivka base from May to September 2022 following the Western provision of HIMARS to Ukraine and the more recent withdrawal of some BSF surface elements from Crimea suggest that preemptive fears of Ukrainian strikes can compel Russian forces to withdraw military assets further into the rear.[29] Several Russian milbloggers accused other milbloggers of spreading panic by publishing images purportedly showing the aftermath of Ukrainian strikes in Crimea in late July 2023.[30] Crimean occupation head Sergey Aksyonov announced on August 14 that Crimean occupation officials will propose amendments at a federal level to increase the liability for the spread of photos and videos showing the location and operation of Russian air defense systems, other systems, and military and strategic assets, indicating increased concern over Ukrainian strike capabilities.[31]

A sustained and expanded Ukrainian strike campaign against Russian military targets in Crimea would likely degrade Russian efforts to defend against Ukrainian counteroffensive operations in southern Ukraine. Ukrainian strikes against Russian military infrastructure in occupied southern Ukraine often cause Russian occupation officials to temporarily suspend transit, disrupting key Russian ground lines of communications (GLOCs) connecting Crimea to occupied Kherson Oblast for periods from a few hours to a few months.[32] Disruptions to Russia’s southern GLOCs have created severe logistics delays and bottlenecks, as the only routes to or from Crimea to occupied Kherson Oblast or Russia are a limited set of bridges. Suppressing or destroying Russian air defense capabilities in southern Ukraine would increase the vulnerability of these GLOCs to Russian ground operations in Kherson and Zaporizhia oblasts. Sustained missile strikes on Russian offensive air capabilities would likely strain Russian aviation attempting to conduct strikes on Ukraine by increasing their flight time, thereby decreasing the loitering time for Russian aviation to conduct strikes on Ukraine.

Sustained long-range strikes against Russian military targets in Crimea could additionally force the Russian military to move military assets and command centers farther away from the frontline, disrupting command and control. Russian milbloggers acknowledged that Western-provided HIMARS forced the Russian military to establish and execute a withdrawal plan from the Russian military base at the Kherson International Airport Chornobaivka (1km northwest of Kherson City) that concluded in September 2022.[33] ISW has also observed reports that Russian forces have moved command headquarters out of range of some Ukrainian platforms in an attempt to protect command centers from HIMARS and other long-range missile strikes after summer 2022.[34] A sustained and successful Ukrainian strike campaign against Crimea could likely achieve similar effects.
...

Ukraine sees Crimea as Ukraine's territory and occupied it before Russia invaded a few years ago.  It is clearly vulnerable to Ukraine attacks and Russia has so far not been able to stop them.