How do I Make a universal menu?

There are so many different problems in your post, it's difficult to follow.

I want it to have a master UI to select from, not have to copy/paste the HUD into each layout, as this causes issues if i update the HUD design, I want all layouts to get that same HUD change without me copy/pasting to every layout. Is this possible?

Yes, that's what Global layers are for.

construct.net/en/make-games/manuals/construct-3/project-primitives/layers

I am already using save game to slot and load game from slot with naming, then using goto layout to load the layout, but the players inventory is empty regardless.

System Save/Load actions save everything, so the inventory should be saved too. If not, this means you are probably clearing or re-creating the inventory on start of every layout.

Well, something else i found out today, my save game using the save slot, translated into the deployed build, so on a different android device, it loaded my last save slot, no inventory, just location, that i had saved in the development environment. Why would it do this?

This is not possible. You must have saved the location somewhere in the project. Run a remote preview, open it in a private Chrome window and check if you can reproduce the same problem.

From the list of answers in the order you answered them in (thanks)

*Thanks, I didn't see the global layer and that is fixed.

The Save / Load is actually doing what I have said, I do not have a hard coded player load position in play other than the start position on the layout as a default position that is overridden if the load event runs, simply System -> Load game from slot "save1", I have spots on the map where saving can occur, waypoints, so when a player touches the waypoint, the game saves. This uses System -> Save game to slot "save1".

While in the editor on my PC, I touch the spot on the map with the player and it saves to save1 slot. Then I can build up the app and publish to google play, when loading the game on my phone, touch my main menu Load Game which uses Load game from slot "save1", it loads and takes me to the layout and the last position I had in my editor. This should not be possible, but there it is, it is what it is doing, and only coordinates, not inventory.

I have also ran into another issue with Google Play, it works on the Android to sign me in ok and I see my typical "welcome" popup, but when trying the login on the PC, it shows the web page to login, I choose my profile, sign in, it returns to the game just fine, but at no point can I get information about the player.

I know you can't get anything until the player is signed in, but after signing in, I do not get the GooglePlay.MyID, I have been through those documents pretty thoroughly and have both the firebase stuff setup and the play console stuff setup, even tried to use System -> wait for previous actions in a sub event on the Google Play sign in event I have setup but it doesn't wait and Is Signed In doesn't seem to trigger nor does Is loaded nor On loaded, or even On signed in, so still working out the why.

Many thanks for your pointer on the global layer thing, that solved a ton of cross layer issues with the HUD i designed.

Randomly, while fighting a monster, the game runs the Load game from Slot, which also doesn't seem possible, it is basically like it is reloading the layout for no reason at the last save, this is completely random, sometimes it never happens but rarely it does. Not entirely sure why on that either, seems a little bit of a bug, been through my layouts a lot to try to find if there is some weird logic, but it never happens in the editor, only in the live game.

Thank you very much for the link, I will go through those and see what else I can find and learn from. Hopefully I can get some of these final issues worked out in the next few weeks of working through them. Your assistance has been very much appreciated.

I regularly look at the examples and what asets there are (green in the screenshot). When I started learning the engine I often looked at documentation and help (yellow on the photo). I also watched youtube, but I didn't save the links, it was a long time ago.