Wow.
Ok, I don't have anywhere near that amount of media, but MythTV takes seconds to rescan ~2TB of videos and maybe a minute to get any missing details like fanart, etc.
Similar amount for music - but I feed it the files after I've run them through Picard.
I've not done a complete rescan of eveything for ages, but from memory it's like an hour absolute tops. More like ~30 mins.
And that's on an underclocked CPU (for quietness).






Your quirky quest to quit using quizzical words is quite strange...
I'd expect that a dashboard / sidebar item could be available only if that module was installed - like Integrations for example.
I use the Energy but not Climate, but in the future I might install it, likewise I might remove an existing one.
I don't see this as a big problem, but I do agree that automatically adding them can be annoying with multiple phones / tablets / etc.