Efficient way to upload FTP data

Hello,

I have a few, battery powered remote devices which upload daily data to an FTP server through 2G network (Eastern Europe). I was wondering if the same FTP connection could be possible using newer network protocol (e.g. 4G, NB-IoT) module?
It would be nice to be able to run these devices from only one Lithium cell (2G modules are power hungry, they require at least 2 cells in series).

Could you recommend some type of module, which can be operated from one lithium cell? As upload is done once a day, some kind of sleep mode would be necessary for modem/module to achieve very low power consumption during the day.

Thanks in advance.