My straight lines are always on different layers

By "extra weird options" do you mean the Contextual Task Bar floating at the bottom of your first screen shot? If so, they're not weird, they are the usual options for a vector shape layer. Personally, I like that they added that, because it used to be harder to figure out how to change the color and other attributes of a drawn vector line. Now it's easier. Also, the Contextual Task Bar is now the easiest and most direct place to adjust the new arrowheads.

Now, if you feel you must reject all that convenience, that's fine...open the Window menu and deselect Contextual Task Bar.

And Ged_Traynor showed how to put them all on the same layer using Combine Shapes.

One question to ask…do you even want these lines to be vector shape paths, or did you want them as pixels? If you want them as pixels, don’t use the Line tool, instead draw straight lines with the Brush or Pencil tool: Set up the tool with the color and size you want, then click to start the line and Shift-click to end it. Those will all end up on the same layer, and not be editable as lines later (because you won't have options like path handles, stroke width, and stroke color that you do get with the vector Line tool).

@Ema35383097kbpq in the options bar for the line tool, set it to combine shapes

If you're referring to the contextual task bar, you can disable it from the window menu