Cannot import SSL Client Certificate (.p12)

Steps to reproduce

1. Launch the Nextcloud IOS app (5.4.1) and enter the URL to our NC server
2. A popup is shown saying that "the server is requesting a client certificate", as expected
3. When browsing to the client certificate (.p12, generated with OpenSSL with the legacy flag) and entering the password for the certificate, we go back to the first popup saying "the server is requesting a client certificate", and we are looping

Expected behaviour

The client certificate should be imported into the app and sent to our NC server when connecting.
Note that the same client certificate is correctly installed through Safari and we correctly connect to our NC server through Safari. It only fails when using the NC ios app.

Actual behaviour

The client certificate is not imported into the app and it is looping on the import steps.

Screenshots

Logs

Apache Server log:
[Thu Jul 04 09:42:59.814730 2024] [ssl:error] [pid 270191:tid 140260126217984] [client x.x.x.x:57011] AH02261: Re-negotiation handshake failed
[Thu Jul 04 09:42:59.814859 2024] [ssl:error] [pid 270191:tid 140260126217984] SSL Library Error: error:1417C0C7:SSL routines:tls_process_client_certificate:peer did not return a certificate -- No CAs known to server for verification?

Reasoning or why should it be changed/implemented?

Environment data

iOS version: IpadOS 17.5.1

Nextcloud iOS app version: 5.4.1

Server operating system: AlmaLinux 8.9

Web server: Apache

Database: Postgres

PHP version: 8.2.16

Nextcloud version: 28.0.2