Relinking generally happens by timecode and metadata in Resolve, filename is usually the last thing Resolve cares about (unless you force it to match).
Generally what I do is import the Hi Res footage to it's own bin, then in my timelines disable Conform Lock for the clips I want to swap out, then from the bin right click on your timeline and select "Reconform from Bins." Just point the re-conform to the bins where your high res media is and it will usually figure it out for you. Depending on how you set up your project you might have to change some scale interpretations, but that's usually it for me.
If your footage doesn't have timecode or metadata you're going to have a bad time, but you can also Relink to different footage on the drive from the Media Pool, but that's kind of an awkward workflow for Resolve.
Edit: I should also say, unless I'm conforming another editor's project, I just don't use proxy media in Resolve. And if you're reading big files off a slower drive, source caching is your friend