I have seen the Victron Multi highly recommended specifically for LFP systems versus the Mastervolt. The reasoning was that the Victron was able to be set to match the specific low and high voltages necessary to care for your LFP batteries. They both have good reputations in the marketplace but the times I have looked at Mastervolt they did seem overly complicated with many add-ons required and not good information on exactly what I would have needed. It looked to me to be both more complicated and more expensive overall.
I am having difficulty sourcing LFP cells right now, at least the brands I want, in the US. So good luck with yours. You should be reading the active (and huge) thread on LiFePO4 battery
systems on CF if you have not. A ton of good info on there, but many opinions on what is best, etc.
We would all appreciate if you could contribute to the thread as you get your system together and later as you get experience with it.