Workaround for https://github.com/NixOS/nixpkgs/issues/226339

pcloud.nix

{ pkgs, ... }:
let
  patchelfFixes = pkgs.patchelfUnstable.overrideAttrs (_finalAttrs: _previousAttrs: {
    src = pkgs.fetchFromGitHub {
      owner = "Patryk27";
      repo = "patchelf";
      rev = "527926dd9d7f1468aa12f56afe6dcc976941fedb";
      sha256 = "sha256-3I089F2kgGMidR4hntxz5CKzZh5xoiUwUsUwLFUEXqE=";
    };
  });
  pcloudFixes = pkgs.pcloud.overrideAttrs (_finalAttrs:previousAttrs: {
    nativeBuildInputs = previousAttrs.nativeBuildInputs ++ [ patchelfFixes ];
  });
in
{
  nixpkgs.config.allowUnfree = true;
  environment.systemPackages = [
    pcloudFixes
  ];
}

Thank you. Worked well for me as well.

If using home-manager, swap out the environment.systemPackages part with:

    home.packages = with pkgs; [
        pcloudFixes
    ];