I know what you're after nejcek74, because I'm after the same thing. The short answer is "No, but..."
To mimic the "force guide line" command, do the same thing you did in v18 (i.e. hover over a point / line, press your short cut key if you don't want to wait). The difference is:
1. They are now called Snap Guides, not Guide Lines.
2. They will only show up when your cursor is near their projection angle (they won't show all the time).
3. They are a different colour (blue by default).
However, they will still disappear when your command is complete - just like the old Guilde Lines used to.
All this you already know. What you may not know is: If you want to make the Snap Guide infinite and always showing regardless of where your cursor is, right-click on the Snap Guide and select 'Pin Snap Guide' (you can assign a shortcut key to this). This is as close as you can get to the old Guide Line behaviour.
There is no way I know of to turn a Snap Guide into a Guide Line.
So, to summarise:
1. To make a Snap Guide show immediately, be infinite, and always show for the duration of the command (i.e. like the old Guide Lines), you will need two short cut keys. One to force the snap reference, one to pin the Snap Guide.
2. To make a Guide Line infinite & permanent, you have to drag from the edge - there is no short cut key...yet.