Don't worry, two 4s batteries in parallel is what Steve from Overkill recommended it sounds like there have been plenty of people running this configuration with no problems.Appreciate the clarification here. My plan has been this exact configuration so was quite nervous reading the earlier posts.
I too am a little confused as to why you would want 2 BMSs on a single 4s - to pull twice the current? Note, still new here and reserve the right to pull the newbie card.
As far as why I could consider this @smoothJoey mostly outlined my use case with one addition I hope to add an additional 280ah battery in the next few years so having the two BMS's already makes that simpler. But mostly it is because I am a noob and the Overkill is easy to understand and highly regarded.
I am planning to use a 200a Daly here is hopeing the lack of documentation doesn't burn me.