The Sublime Text package "rainbow_csv" has the wrong color palette

Question

I've installed the Sublime Text Package "rainbow_csv", but the colors are all wrong.

It's not "rainbow" at all - just muddy colors, with a grey that blends into the background like a comment. And white appears redundantly for both the 1st and 3rd column.

So I want to customize the palette.

I've tried following the instructions in the GitHub repo, but nothing changes.

RainbowCSV.sublime-settings ↓

// Use custom high-contrast rainbow colors instead of colors provided by your current color scheme. 
// When you enable this option, "auto_adjust_rainbow_colors" also gets enabled by default.
"use_custom_rainbow_colors": true,


// Auto adjust rainbow colors for Packages/User/RainbowCSV.sublime-color-scheme  
// Rainbow CSV will auto-generate color theme with high-contrast colors to make CSV columns more distinguishable.  
// You can disable this setting and manually customize Rainbow CSV color scheme at `Packages/User/RainbowCSV.sublime-color-scheme`, you can use the following [RainbowCSV.sublime-color-scheme](https://github.com/mechatroner/sublime_rainbow_csv/blob/master/RainbowCSV.sublime-color-scheme) file as a starting point for your customizations. 
// Do NOT manually customize Packages/User/RainbowCSV.sublime-color-scheme without disabling this setting, the plugin will just rewrite it in that case.
// This option has effect only if "use_custom_rainbow_colors" is set to true
"auto_adjust_rainbow_colors": true,

This error appeared when I installed the package. It seems to be related. But I don't have any leads as to what caused it, or what to do about it.

Error loading syntax file "Packages/rainbow_csv/pregenerated_grammars/CSV(Rainbow).sublime-syntax": Unable to read Packages/rainbow_csv/pregenerated_grammars/CSV(Rainbow).sublime-syntax

_{Sublime Text Ver. 4126}