Most likely this is caused by interference between the Elementor plugin and the Monstroid 2.0 theme. As you can see from its developer’s page Monstroid comes with a plugin called Kava Extra. This plugin, now discontinued by its developer, contains templates for the Kava Theme, which also depends on Elementor.
I’m not 100% sure how this works, but I would say that the Kava Extra plugin is installing the theme (hence its return after you deleted the database entry). However, for some reason it does not complete the process by registering it for display on the themes page. That may be a bug in Kava. Perhaps either Elementor or Monstroid is doing something to prevent or annul it.
Also, you may not see Kava in your plugin list, because it is bundled with Monstroid and activated by the theme.
Now, should you install the update? I have no idea. This depends on which components of Kava (if any) are used in the Monstroid child theme you have installed. Or maybe some settings in your Elementor plugin make it critical. You may miss out on nothing if you don’t update or you could miss an important security update. Backup your site and try…