You need to check the settings of the app you are clicking links in. There may be a setting for where to open links in. For example in gmail the setting is "Open web links in Gmail: Turn on for faster browsing" unchecking it will make gmail respect your default browser settings.

That worked for Telegram, but some apps don't have that option. Is there a way to just disable that functionality in Firefox?

Hi

I should be able to help with that:

1. From the Android home screen, open the Settings app and scroll down to Apps.
2. Scroll down the list to Firefox and select it.
3. Scroll down the screen and select Clear Defaults.

I hope that this helps, but if not, please come back here and we can look into a different solution for you.

I don't have the Clear Defaults option.