I think it would be really intuitive to be able to open all tabs from another device by long pressing on the device name on your mobile device and selecting the option.
You can open all synced Tabs from another device in the desktop version (Firefox for Linux Mint 107.0) already by opening the sidebar, selecting "synced tabs" and right-clicking on the device, but when you add the "show tabs from other devices" to the toolbar and click on it, there are no options displayed when right-clicked, although it is even better reachable than the sidebar in my opinion.
Additionally, it would be great to have options like sharing, opening in new (private) tab, copying a link and maybe even opening in app (if possible) for the list of synced tabs after long pressing on them on mobile.