I think ultimately you are perhaps concentrating on the issue of 2 or more partitions existing for an extended period of time.

There is no consensus algorithm now or in the future, which can solve that issue without the destruction of data or entire partitions.  Not POW, POS, POI, trust models or anything else.

If the partition duration is short, the more likely it is that you can merge and resolve P with no data loss.  It is my opinion based on fact and research that blockless data structures can achieve better results and less data loss than block based ones.