Hi @musicalBox, sorry for this late reply to your post but your demo is fantastic and will no doubt have been really useful to show @anon78133251 how to create this effect. I appreciate you posting it! Great work! 
As it happens back in November started making a YT tutorial on how to do a very similar effect - I completed 90% of the tutorial but then had to put it on hold because a) I wanted to wait until the “Size Position and Rotate” minor bugs were fixed in v.20_11_28 and b) I have been busy writing and arranging some Christmas music.
The tutorial shows how to make this actual effect:
and also how to adapt it for a nice lower thirds effect:
My method was very simialr to yours, using simple text filters and masks. The main difference was that I showed viewers how to first export the animated line (white line with black background) then re-import it, adding blend mode: add, and re-sizing it.
Once I’ve got my Christmas Music projects done and dusted I’ll revisit my text effect tutorial and post it.