I’ve been having similar issues on a system where I upgraded the solar production to almost double of the recommended, when judging by the battery storage available. Here is my recent post. Indeed, according to my observations, even the MPPTs don’t seem to be able to get in-sync with the rest of the system quickly enough, hence I’m having a “charge/discharge vibrating” issue with a period of 2-3 seconds. Not optimal, since this whole ordeal is stressing the system and particularly the battery. Of course, this ONLY happens when the battery is full, thanx to LFPs’ voltage peaking too fast. One way to correct this would be to set a lower charge voltage. That way, “energy dumping” would take place in a more flat portion of the charging curve, and any battery would take that load. However, lowering the charged voltage too much, would make the balancers to ever start, eventually turning the battery off-balance and hence a single cell would then still reach too-high of a voltage.
tldr; I don’t really have an answer to your question, just some additional input. However, I would have to ask; what kind of a distance are we talking about? There are 250V MPPTs now out from Victron, and you can easily carry 200V of DC over long distances.
Oh, and there definitely is no chance of a fire breaking up, you can surely forget about that.