various: normalize flatpaks and downgrade linux kernel temporarily

hosts/shared/nixos-pc.nix

@@ -20,7 +20,10 @@ in
     consoleLogLevel = 3;
 
     # Use latest LTO optimized x86_64-v3 kernel from CachyOS.
-    kernelPackages = pkgs.cachyosKernels.linuxPackages-cachyos-bore-lto-x86_64-v3;
+    # Disabled temporarily due to HDMI bugs.
+    #kernelPackages = pkgs.cachyosKernels.linuxPackages-cachyos-bore-lto-x86_64-v3;
+
+    kernelPackages = pkgs.linuxPackages_7_1;
 
     extraModulePackages = [ config.boot.kernelPackages.kvmfr ];
 
@@ -74,6 +77,27 @@ in
       })
     ];
 
+    flatpak = {
+      packages = [
+        {
+          appId = "com.usebottles.bottles";
+          origin = "flathub";
+        }
+        {
+          appId = "io.github.ungoogled_software.ungoogled_chromium";
+          origin = "flathub";
+        }
+        {
+          appId = "org.gtk.Gtk3theme.Breeze";
+          origin = "flathub";
+        }
+        {
+          appId = "io.mpv.Mpv";
+          origin = "flathub";
+        }
+      ];
+    };
+
     # Configures snapshots for home subvolume.
     # Requires /home/.snapshots subvolume to function.
     snapper = {
@@ -344,10 +368,8 @@ in
       openjdk25
       tmux
 
-      unstable.winetricks
       unstable.fastfetch
 
-      inputs.nix-gaming.packages.${pkgs.stdenv.hostPlatform.system}.wine-cachyos
       inputs.appimage-manager.packages.${pkgs.stdenv.hostPlatform.system}.default
 
       (python3.withPackages (
@@ -395,12 +417,6 @@ in
       DOTNET_ROOT = "${pkgs.dotnet-sdk}/share/dotnet";
       DOTNET_CLI_HOME = "$XDG_DATA_HOME/dotnet";
       GTK2_RC_FILES = "$XDG_CONFIG_HOME/gtk-2.0/gtkrc";
-      WINE_BIN = "${
-        inputs.nix-gaming.packages.${pkgs.stdenv.hostPlatform.system}.wine-cachyos
-      }/bin/.wine";
-      WINEPREFIX = "$XDG_DATA_HOME/wine";
-      WINEDEBUG = "-all";
-      DXVK_LOG_LEVEL = "error";
     };
   };