This is the 3rd project ive made thinking it would make a difference; Im not sure what im doing wrong.
I just created a fresh new game from the 3rd person template: made a blueprint of the GameMode and set it to the default game mode in the project settings.
Create a Hud with a Text on the canvas, just to show it was on screen.
Created a blueprint of the HUD, from where I have the widget blueprint added to viewport.
Maybe you need to specify owning player (controller) to create widgets from other blueprint classes (not all of them but give a shot) maybe its cause of that.
Edit: Also in new game mode since you created one and if some widget appearing I assume you set hud class already in game mode?
I appreciate the help!
I have tried specifying the owning player before, and it didnt work–i was copying a tutorial but I was doing it on a template; they didnt need to specify what controller is calling the Create Widget node and just left it empty.
I made a BP from the HUD base class just to be sure. I had the correct Game Mode assigned, assigned the BP_HUD and tried adding the widget and add to viewport from it–it also didnt work.
I have an update: I tried redownloading UE5.5.4. I made a blank game and the UI works as intended, perhaps its some bug. I have also tried it on my laptop (im using my desktop, where the issue exists), and it all works fine. My next move is to replicate the issue with the 3rd person template again.
Update #2:
I tried it again with my laptop- it might be a bug with the 3rd person template.
Created projects for a 3rd person and FPS template, simply made a new Game Mode, HUD, and Widget.
The 3rd Person template still wouldnt display the widget to the viewport, BUT the FPS template does display it.
Are you doing PIE as a client? gamemode only exists on the server so that could explain why it doesnt work when you put BP in the gamemode rather than the character
which is hardest bug to solve 
