It's so silly that you can't make a dashed line in the entire program

No native way to do this now. Many users have requested.

See discussion thread : 

https://community.adobe.com/t5/premiere-pro-ideas/add-ability-to-draw-a-simple-dotted-line-within-premiere-pro/idi-p/15450913

You can use After Effects if you have it. Various videos 

I agree a native tool in Premiere would be useful