Spotlight indexes on-the-fly so new and changed files are quickly searchable, but periodically needs to assimilate those into its more static indexes. That and Live Text extraction are run following startup.
mediaanalysisd
You can disable Live Text in Language & Region settings, but what exactly does that do? Does it also block Visual Look Up, or connection to Apple?
How to find images containing objects recognised by Visual Look Up, and text by Live Text, using Spotlight, mdfind and in an app.
How images have text recognised within them as Live Text, and objects of interest are classified, using VisionKit, mediaanalysisd, Espresso, the ANE and more.
The Eclectic Light Company 