I suspect iOS14 did not solve your problem!, and may have made it worse if that is possible.
My eSIM (US AT&T) with Swedish SIM began to have SIM Failure during iOS13.x (not sure which 'x'), but was always able to recover after restarting the phone. With iOS 14.0, the 'add data plan' option has disappeared, and my eSIM has SIM Failure on restart even though the data for the eSIM line (IMEI, etc.) is still there under General/About... . I cannot remove the eSIM data or try to reinstall as 'eSIM installation unsupported on your device' now occurs, and that is clearly wrong since it worked earlier (in Sweden, and eSIM was installed in Sweden for the US line). Apple Care Support (who deal with software issues apparently) has a case open, but I am not hearing anything the past days. The hardware (XS Max, unlocked, bought at Apple Store in US) has been scanned by Apple and is ok, so it's a software problem, of some kind. Bottom line: iOS 14.0 broke the eSIM line completely.