How to Hide i3-bar by default
Regolith version 3.0 onward replaces “i3-wm” with “wm” in Xresource keys. The content on this page has been updated for Regolith 3.0+. If you are using an earlier version, use “i3-wm” instead of “wm” in the key names below. For example changes to for Regolith 1.x and 2.x.

Add the line hide

to $HOME/.config/regolith3/Xresources file. The next time you log in the bar should be hidden by default.