I share this frustration even though i know of several good reasons why it is the way it is. The 12v AIOs don't go past ~2kw. Luckily they are cheap 'enough' that imo it is not ludicrous to buy them as JUST a 450v / 80a mppt at ~$250/pc. There are no >400v mppts of any sort that are cheaper than that, that i know of.
In my RV i ran a 5000w standalone inverter along with a ~1500w 12v AIO being used purely as an mppt/gridcharger, but im planning to convert it to a single 3000w inverter/60-100a charger combo unit sometime this spring and see if i dont regret it.

The high voltage mppt aspect is really only useful to me when the RV is parked at home anyway.