Can you remove the first system barline?

The one that appears on the very left on the first page and that connects all the staves.

(Trying to make my own custom manuscript paper with Dorico. :smiley: )

Yes, as long each system only contains one stave. See https://www.steinberg.help/dorico/v3/en/dorico/topics/notation_reference/notation_reference_barlines_systemic_after_first_system_hiding_showing_t.html

Thereโ€™s been a thread on ways to do this.

https://www.steinberg.net/forums/viewtopic.php?f=246&t=113511