You can open "Synced Tabs" in the sidebar, and right-click a device header to find "Open All in Tabs".

• https://support.mozilla.org/en-US/kb/use-firefox-sidebar-access-bookmarks-history-synced

What do you see if you open Synced Tabs in the sidebar ? Can't you right-click a specific device header to find "Open All in Tabs" ?

okay if I click alt > view > sidebar > sync tabs > right click > open all in tabs it opens them all into one window instead of the many window groupings I have neatly organized; loading 100+ tabs into one window is utterly useless unusable, is a big letdown.

there must be another option. if not, I need to write up a feature request 'open all in tabs and windows' because it doesn't work as it is now. Chrome did it properly.

Synced tabs are uploaded to the Sync server in one payload and doesn't differentiate between windows. I'm not sure if there is a limit to the size of this payload and whether the tabs are ordered by window.

okay if I click alt > view > sidebar > sync tabs > right click > open all in tabs it opens them all into one window instead of the many window groupings I have neatly organized; loading 100+ tabs into one window is utterly useless unusable, is a big letdown. there must be another option. if not, I need to write up a feature request 'open all in tabs and windows' because it doesn't work as it is now. Chrome did it properly.

Yeah, the tab features in Chrome are far better. Which is why I use it work to label the windows and have tab groups in each window.

Videos of Chrome Tab groups

You should just mark this as resolved because there is nothing to be fixed.