On Android, several apps I've tried open links in an internal browser, which defaults to Chrome. Any external news/whatever link is ad-riddled and I have no way to redirect them to Firefox.
In addition, video links open in the official YouTube app instead of revanced, and imgur links open the website instead of an internal image viewer that views the direct image (or something like imgurviewer). Slide used to have it's own internal YouTube viewer which broke only recently, probably because of changes to YouTube.
At the moment, using Lemmy though these apps is much worse than using slide for Reddit was. I almost forgot how terrible the web is for mobile use prior to getting on Lemmy - it's unusable! Are any app developers working on this problem?
In android settings, in the Apps section (Talking about Samsung UI, might be a bit different for you) you can select Chrome and in "Set as default" you can clear the default, and it will ask you again what the default webbrower should be when openning links in apps.
It's already set to Firefox, the apps either ignore the setting or have an internal web browser, which I like in principle, but because it's chrome-based, it has no plugin/AdBlock capabilities
I'm using liftoff. Just rechecked and you're right, it opens web links in Firefox. Unfortunately, it also opens YouTube videos in Firefox and imgur links in Firefox, which is much slower and worse than opening them in an internal viewer or ad-blocking app like revanced or imgurviewer.