Not the author. But thank you, I didn’t know that.

What you’re doing is equivalent to

nix-shell -p "grim slurp"

Which won’t work because nix-shell expects

nix-shell -p "grim" "slurp"

Which then becomes

{...}@args: with import <nixpkgs> args; (pkgs.runCommandCC or pkgs.runCommand) "shell" { buildInputs = [ (grim) (slurp) ]; } ""

According to the manual

nix-shell --packages interprets each command line arguments as attribute names inside the Nix packages collection.

The error message is because you are giving multiple package names as a single argument.

According to one of the maintainers

YouTube/Google has patched the latest workaround that we had in order to restore the video playback functionality.

Right now we have no other solutions/fixes. You may be able to get Invidious working on residential IP addresses (like at home) but on datacenter IP addresses Invidious won’t work anymore.