Which EG4 battery do you have? If server rack, have you taken the top off? The cells are relatively easy to reconfigure to 12v. Admittedly not as easy as other brands, but still not impossible. This could be a solution to simplify your design.
I was in a similar place a few months ago. The EG4 AIO needs >120v in from solar to charge and parasitic draw was atrocious, like 1500w/day. I wound up selling my EG4 battery and AIO for 1300. I only regret selling the battery. For the price, I should have kept it and reconfigured the cells for 12v.
So, for ~$100 you can get a nice 200a bms and make that EG4 a 12v 400ah battery. (Maybe I got lucky selling my AIO, but maybe you would too.) This seems like it could greatly simplify your system!