Unable to sign in to another homeserver on iOS 15 (mozilla.modular.im)

**Describe the bug**

on iOS 15 (might be iOS 14 as well, I wouldn't be able to tell sadly) when opening a link to sign in to a different home server, in this case, Mozilla.modular.im, it opens it in a built in browser, and doesn't open the link in an external browser, it wouldn't be an exact problem, but in Mozilla's case, it is a password-less sign in, which is basically done via opening the link that is sent to your email in the same client / browser tab as the sign in screen.
It is kind of an impossible task to be able to do so, since I cant open the link from the email inside element itself. I also cant use the normal sign in via my Mozilla account, after I click "trust this source" it closes the browser and shows me the sign in button, nothing happens, no attempt to load anything, nothing, it's as if I didn't even do anything although I know for sure that I did.

**To Reproduce**
Steps to reproduce the behavior:
1. Open the sign in screen
2. click on "sign in from external home server"
3. type in "mozilla.modular.im"
4. click on "sign in"
5. type in email
6. Go to email
7. click on link
8. experience pain and frustration
**Alternatively**
1. Open the sign in screen
2. click on "sign in from external home server"
3. type in "Mozilla.modular.im"
4. click on "sign in"
5. click on "sign in with Firefox/GitHub/google account"
6. type in email and password
7. click on "trust this source"
8. wait for it to close the page
9. see no difference
**Expected behavior**

I would expect that when I click the link, it would either give me the approval of signing in to element even though it isn't in the app itself, or when I ask to sign in with my Firefox account, when i click "trust", element wouldn't act as if I had done nothing/

**Screenshots**
I cant really take any screenshots without somehow exposing my email

**Smartphone (please complete the following information):**
- Device: iPhone 7
- OS: iOS 15.0 developer's Beta 1
- Browser: Safari + native Client
- Version: Element v1.4.1

**Additional context**
Not quite sure if this is a problem with either Element, iOS, or Mozilla, either way it is a bug