Local data storage

Issue: Due to uncertainty of Internet connectivity in the place I will deploy RAK7258 I was wondering how to save the incoming data from devices.

Setup: Lora Device -> RAK7258 -> SD card OR Webserver\MQTT\NODE.RED on Raspberry pi

LoRa® Server: RAK7258 Local LoRa Server

Details: I want to log the data from lora devices to a local server\DB\CSV file. Let’s assume I managed to connect the LoRa part. How would I go to:
A. Save the RAW data at RA7258 SD card - To be post processed manually later.
B. Forward the data using MQTT or HTTP to a local server or broker?
C. Decode the packets and save them in a CSV format (or an easy to use DB).

Does anyone have any reccomendations? Links?
Any help is appreciated!