This exiftool command will copy the keyword tags from a source file to a destination file.
exiftool.exe -tagsFromFile SOURCEFILE.jpg -Subject DESTINATIONFILE(S)
I work with Lightroom, so the following vocabulary comes from that.
The SOURCEFILE needs to be an exported file (jpg, etc.). LR doesn't change raw files, including exif data. Keyword tags get added on export.
The DESTINATIONFILE can be an export or a raw file. exiftool will write to either.
To get to your specific question, the DESTINATIONFILE can have wildcards. So if you want your source list to be copied to, say, all the .CR2 files in a directory, the command would be:
exiftool.exe -tagsFromFile SOURCEFILE.jpg -Subject DIRECTORYPATH\*.CR2
As with all command-line stuff, directory paths to your image files need to be spelled out for everything.
Quick note on the command. The -Subject option is actually specifying the exif tag you're looking for. That exif tag contains a comma-separated list of your keyword tags.
Subject : !Published, 01_Instagram, 01_Washington, 2021, Bridges, Columbia River, Industry, Infrastructure, Mountains, Nature, Othello, Roads, Snow, Transportation, Trucking, W.01-15, Week08, West
I was about to say that your list will come over exactly how it looks in the source image and that your hierarchy would be fine. But now that I look at that list above, it's in alphabetical order. That must be the way LR spits them out. Don't know if that would be a problem for you.
There's also a command to write exif tags from a text file to image data. You might use that to rejigger your list order to accommodate your hierarchy then write that edited list to your target image files with a separate command.