Do you still HAVE 3G in Sweden? Everybody except AT&T has discontinued it here in US. AT&T (US) was shutting 3g down in January 2021, but it's been extended because of COVID. Other carriers have already dumped it. The only reason why AT&T kept it this long is because there are still a lot of medical devices that rely on it.
If all else fails, try this.
https://wiki.mobileread.com/wiki/DuokanDon't know if it works with D2 though.