Agreed. For some reason the lock pad is a few millimeters narrower than on the Xperia XA2.
Check this thread to get involved in supporting 4G/VoLTE with more operators: https://forum.sailfishos.org/t/c2-volte-testing-instructions/21168?u=jojomen
I understand that you report these here as general feedback on the C2, which is fine.
To resolve your issues, I’d suggest opening separate support/bug report threads. It would be of general interest to improve imports, or at least throw meaningful error messages. Having these issues in threads of their own would also help other members find them.
For the problem with duplicate entries, @dcaliste may be able to help you clean up you local calendar so you can import them again. (I have dabbled with the calendar db, but I’m not confident enough to guide you.)
It’s not so much a re-write into a new language as adapting the ever-evolving Firefox to SFOS GUI and infrastructure.
If you’re interested in the technical details, check out flypig’s blog on the most recent lift from Firefox ESR 78 to ESR 91. It’s a really interesting read. You can also find his Fosdem talk on the topic here: FOSDEM 2024 - Daily blogging embedded Gecko development
If you just want the tl;dr, here it is: This no-brainer is a big-brain effort.