I'm not super techy, but I think the app has to say somewhere what links it can open itself. I know Jerboa can be used to open Lemmy links; but it seems to be the only Android app that can, for some reason.
The app has to define specific links, so Jerboa just has a long list of instances copied from wherever. I wonder if Android supports changing these from the app itself?
I don't think it does that I know of. A freely hosted list of links that each app could include at build stage would be pretty good and easy to incorporate into the pipeline.
Summit can also do so, although its list is more limited than Jerboa's.
Are you talking about lemmy links? If so, you can force an app to open them but it depends on your phone manufacturer and whether or not that setting is hidden. For Xiaomi, you need an app to access hidden settings (you may want to enable a DNS adblocker or something similar before using this) so you can force your chosen Lemmy app to open all Lemmy links in-app.
edit: for any Xiaomi users that read this in the future, download the app I linked above ("Hidden Settings for MIUI").
verified links header should be an "Add link" button, click that and tick every option that pops up. If 
Add link doesn't appear, then your Lemmy app hasn't associated any links with itself - let the dev know, because they need to do this otherwise the app is not capable of opening Lemmy links! Right now, only Summit and Jerboa seem to support opening Lemmy links.Are you talking about lemmy links?
Oh yes, sorry, I edited my post.
I've got a Samsung S21FE.
Try this guide (teddit mirror, libreddit mirror); look around for how people do this for Revanced because it's a very common question that comes up and someone might have the answer for you.
Also, only Summit and Jerboa seem to support this at the moment. @liftoff@lemmy.world needs to add link associations in the Liftoff app :)
Try this guide (teddit mirror, libreddit mirror); look around for how people do this for Revanced because it's a very common question that comes up and someone might have the answer for you.
Also, only Summit and Jerboa seem to support this at the moment.
A mobile client for Lemmy running on iOS and Android