A recent update removed a great feature. On Desktop Firefox, I used to be able to open the Tabs From Other Devices Sidebar, and right click on (say) Pixel 7 > Open All Tabs.
This has been removed recently and I can only left click a device to collapse all tabs underneath it.
This was a really good feature. It was the quickest and most reliable way to move dozens of tabs from mobile to desktop. I can still push, not pull (i.e. on mobile select all tabs > share > Firefox Desktop) but this is very unreliable. They only push 3-4 at a time, and recently I pushed ~ 80 tabs but only 40 arrived, which I realised after closing (I'm now manually reconciling tabs to ensure they made it which is ridiculous).