Not Starting

I don't understand the mechanics of vehicles, but I have a 2014 model vehicle that I have had for 6 years, the vehicle has not been used for a long time, but I run it regularly every week, make 1-2 laps and park the battery etc. It's not meant to end. However, yesterday and today, when I turn the ignition, clicking sounds are heard and the starter does not start, the screen says immobilizer failure, and when I turn the ignition off for the second time, it says airbag or seat belt failure. If it was a battery, I think the headlights, tape or windows wouldn't work. Why can this happen in vehicles that lie for a long time? Can anyone recommend someone who can solve this problem around Çekmeköy-Ümraniye?

Thanks in advance

One or two trips per week is not enough to charge the battery.