Have you witnessed the congestion in LoRa (on meshtastic? or?) in Portugal last year at the apagon day? Or this is just calculations? As I remember people mostly just were listening to FM radio, but I'm not sure what was the real situation in 868mhz that day as I didn't have meshtastic installed.

I'm living in Germany and wasn't there that day. This info was from the GNPA (Grupo Nacional de Preparação e Autosuficiência) when we had events together during summer. They basically prepared for this in advance and on the day something happens, the network is congestionated around urban areas. Later this year we'll present a more robust solution based on Wi-Fi/bluetooth and radio. Lessons learned.