I've tried a lot of similar tools for sending files between devices in local area network and found that https://localsend.org works best. Yes, it requires an application installation, but the transfers are much more faster and reliable when browser is not involved. And its Android application works nicely on Google TV/Android TV, so I can send files there easily.
I struggled so long with having to use Chrome for translations on Android until I found out that my favourite translating extension works with mobile Firefox just perfectly. See [3] on how to install it in Firefox Beta (maybe this method or even the extension itself is already available in Firefox Release).
I am using a similar extension Session Sync, but it exists only for Firefox and has an ability to sync sessions. It just saves sessions as bookmark folders, and sync is done natively by Firefox Account Sync. Despite the last update was in 2019, it still works pretty well.
As I can see from changelog, sessionic also supports sync [3]. It would be nice if it is added to description/readme.
>changed the click behavior of the bar to be totally unlike any other program too
I am using Firefox Developer Edition, and I was also stunned at first a while ago. But now as I'm getting used to it, I tend to like it more and more. It was really hard to select just one part of the path (word) before this change, and now I can just double-click those parts to delete them then (useful when you want to cleanup the URL from some mess).
Also here is the description and justification for this change from OP link:
On Linux, the behavior when clicking on the Address Bar and the Search Bar now matches other desktop platforms: a single click selects all without primary selection, a double click selects a word, and a triple click selects all with primary selection