> ... but on Linux, I haven't found anything that loads as rapidly and without friction
As for GUI-based CSV editor projects, I may highly recommend you also take a look mtCellEdit (C++/Qt[0]) and Tabulator (C++/Qt[1] & Python/Qt[2]) apps.
Both projects are cross-platform & FLOSS (free and open-source software), so available for Linux, macOS, Windows, etc.
FTR, mtCellEdit has a lot of functions especially useful for spreadsheet/CSV data analyzing.[3,4]
[0] https://github.com/matyler/mtCellEdit
[1] https://github.com/notnypical/tabulator-qt
[2] https://github.com/notnypical/tabulator-qtpy
[3] https://doc.marktyler.org/mtcelledit/en_GB/chap_00.html
[4] http://web.archive.org/web/20190913184255/http://marktyler.b...
Correct [2], as it is actually the same as [1].
Ask its developer via issues tracker on GitHub.
Of particular note is this set of extraction features which is where I spend a lot of time http://www.delimitware.com/help.html#_File_Extract_Dialog