F-droid Firefox navigation super slow since last update

I'm seeing what sounds like the same issue.

Based off your comment on extensions, I just disabled all extensions, and the problem went away.

If I enable any extension, it breaks again...

So to me it seems like a bug with the extension system

Edit: tested with Privacy Badger, uBlock Origin, and NoScript

Edit2: Fennec F-Droid build #1420020; Android 16 (GrapheneOS 2025081400)

Edit3: Found a bug report about it: https://gitlab.com/relan/fennecbuild/-/issues/134

I'm having the same issue with Fennec from F-Droid on a Pixel 8 Pro. I thought it was network issues but it happens no matter how I'm connected, WiFi or 5G. Chrome doesn't have the issue on the same phone and all apps work fine so it's definitely a Firefox engine issue.

I'm not seeing this problem on the latest ironfox. Even heavier sites like github load within a few seconds.

On the latest F-droid blog post they listed this as a known issue:

Fennec F-Droid was updated to 142.0.0 and got a lot of publicity, and not for how great it works, unfortunately. It appears the slow spell hit it too as there’s an issue using extensions that use webRequest listeners, like uBlock Origin, Privacy Badger, Ghostery, TamperMonkey and more, that delay the connections to websites on start. For now we recommend to try a couple of things. While disabling these extensions fixes it, we know that the Internet is unusable without ad blocking.

• First trick is to disable the extension, wait, hear me out, just toggle it OFF then ON back again. (Small note here: while there are many ads related extensions out there, maybe it’s time to look at their usage a bit more and decide to keep only one. We’ve seen users installing them all thinking this will cover all angles, while the truth is they are messing with each others rules and you might end up more exposed than less.)
• Second, the issue is seen when swiping the app away (where the app status is decided by Android, Schrödinger’s app paradox), but some users reported success if instead of swiping it you actually close it. The Close button appears in the main menu if you enable “Delete browsing data on quit” in Settings. eg. “Cached images and Files” is the least annoying option to select, careful not to select any of the others. So, when you want to close the app, just use the button and on the next start it should load pages normally.
• Third, our own @linsui pointed that, we can just close the screen. [...] When you open the app, if you see it stand there doing nothing, lock the device and then unlock it. We don’t understand why this works for some, but surely it has to do with libraries and drivers and magic numbers.

As a reminder, there’s a reason why our fork of Firefox is named Fennec, it’s not about some code name anymore, but about the fact that our version is a work on top of Mozilla’s code. We need to extract all the bad (read non-FOSS, read privacy invading) code and give you a clean app that serves you and not some faceless corporation. Are we breaking some eggs to do this omelette? We sure are. And we do our best to serve it fast and tasty. Yet sometimes egg shells might end up in the final product.--

My two thoughts on this are DNS, too:

• The "HTTP over DNS" setting in the browser.
• The DNS setting in your WiFi configuration.

But as you've tried DDG browser without issues, it's more likely to be the first option.

Also, any VPN you may be using.

It seems likes a Fennec and Firefox specific issue. Try Ironfox and see if it behaves differently. Its not on F-Droid. Obtanium is the easiest way to install Ironfox (and keep it updated).

Xiaomi 11T Pro and Fennec from F-Droid with uBlock Origin, Privacy Badger and Consent-O-Matic browser addons. Thought it was my DNS because I replaced my router last weekend. Im glad that I found this post.

Yes, its a known issue since v142.0. You will have to wait or try workarounds to get around this issue.