I've just spent another 45 minutes trying to install add-ons via Fennec ONLY. It just doesn't work. I only have access to "approved" extensions.
However, when I go to my custom collection in a desktop browser I have full access to firefox addons (as you described we would)--but I have to first search and add them to the collection from the desktop browser.
When that's completed, THEN I can go to Fennec and navigate to the collection and tap the "+" sign to install them into Fennec.
It wasn't at ALL clear to me that this entire process takes place in two DIFFERENT Firefoxes: one on a desktop or laptop install and THEN on your android device!! Maybe I read thru the instructions too fast (real men don't read instructions 😉 ) but they all seem to say "...open Firefox..." without being clear WHICH Firefox they're referring to.
I've now spent close to 3 hours trying to get 3 extensions to work/load properly into Fennec on the Android... Back to Kiwi! "It just works..." 😡
I've been trying to follow your guide for an hour now--but I'm not getting access to any add-ons but the "compatible" ones. For example, when I search for 'Cookiebro', the only two choices it shows me are Ghostery and uBlock Origin.
Yeah, none of this is on the NY Times website, for example. Not that that's the final word--but I'd be more inclined to believe them than whoever The Enforcer is...
I've been using FEEDLY for years. Love it.