I don’t a Obsidian based solution to bulk replace content of notes. In the past I’ve used vscode to do some bulk search n replace of my Obsidian vault. See this post Batch Cleaning Mark down files before pasting into Obsidian folder in Windows explorer - #2 by efemkay
I hvnt used standard quick switcher awhile (so i guess the look changed). I use “Another Quick Switcher” plugin now. Also u didnt attached any screenshot.
Obsidian indexes all supported files in ur vault and keep that index in a separate db file. So it can afford to know that [[note a]] actually located in some folder within another folder. But if u open this in another markdown app (like zettlr, vscode with some plugin), they wont know, so u need to use relative path. But there’s a few plugin that allow u to convert that. So don’t have to worry for now (unless u really want to use multiple app concurrently)