488 Electrical Problems

I’ve got a 2017 488 GTB with 4000 miles on it. Drive it every few weeks, and leave on factory charger in between.
Yesterday took off charger and drove mostly at freeway speeds for 40 minutes, then a couple of shorter trips, then 40 minute freeway trip home. Started fine each time. Seat heaters, radio, fan and lights on all the time while driving. Turned off car when arrived home, then tried to restart about a minute later. Acted like battery dead. Engine would not turn over. Multiple fault codes. Electrical system was all bonkers....couldn’t turn off lights or fan with switches, one door locked one not, trunk wouldn’t open...all symptoms of very low battery.
Similar problem about 6 months ago...had to get towed to dealer...dealer diagnosed as bad battery. Had to get towed to dealer again...battery would not charge with trickle charger, and inability to get into trunk made jump impossible.
With this happening again, it seems like car is discharging while driving, down to zero. And doing it repeatedly until it kills battery.
Alternator problem?
Anyone with similar experience, and solution?