When you create a 3D project it doesn’t import the 2D GameObjects.
Go to the Package Manager
It will need to compile.
You should now have 2D objects in the GameObject menu.
You might also want to add:
- 2D SpriteShape
- 2D Tilemap Editor
- 2D Pixel Perfect
Now you have everything you should need.
When creating a Scene remember to set it to 2D.