Heroic Games Launcher games, when launched from Steam, don't use the set cursor theme

Hello, this is a bit of a weird one. I use the flatpak version of Heroic Launcher and I set it to put games it downloads on Steam automatically.

When I open a game from Heroic that doesn’t have a set cursor theme (e.g. The Alto Collection) in Heroic itself, the cursor stays what I set it to. However, when I launch the same game from Steam, the cursor uses the default black XCursor.

If anyone could point me a way to fix this, I appreciate it.

If needed, here’s my home.nix (made with home-manager):

{ configs, pkgs, ... }:

let

  pkgsUnstable = import <nixpkgs-unstable> {};

in

{
  users.users.anon.isNormalUser = true;

  # Home Manager configuration
  home-manager.users.anon = { pkgs, ... }: {

    # GTK theming
    gtk.cursorTheme.package = pkgs.bibata-cursors;
    gtk.cursorTheme.name = "Bibata-Modern-Ice";
    
    gtk.iconTheme.package = pkgs.papirus-icon-theme;
    gtk.iconTheme.name = "Papirus-Dark";
  
  # rest of home.nix
  }

Thanks for your time and any answers!