Displaying thicker lines in easy toggle on off mode how best to do this?

I am happy working with the default lines most times, though if I want to send someone a printscreen the lines are too fine.
I right click in viewport on e.g. Top wording and choose print display.
In the layer for the line I choose Print width and make it thicker and see no chage, I make it the max 2.0 and still no change.

why ?

What is best to display on screen a thicker line and have a quick way of toggling this on and off ?

V4 and V5 (teething on latter)


Hi Steve- if the curves are on layers that have line thickness applied and have their own thickness applied by layer (default) then you should see them fatten up with ‘Print preview’ in the viewport menu. Post an example that does not do this and I’ll take a look.