So seeing that combo in the video above along with a combo variation I saw a JP player do, I came up with a new BNB at certain ranges from the corner (this might be known already but might as well post it)
5B 2C ItsuuA 6kote Haku Hatsu RiichiA IppatsuA IppatsuB delay tk.Hatsu Haku Chun 2D (staff must be about no further than a 4kote from the corner for this to hit) late j.C staff2 2C ItsuuA 4kote 3C 2D 6C 6D Daisharin (optional)
Hits 5K (don't have exact numbers right now, no game available to test) works on everyone. Off of 2C starter you can get an extra ItsuuA repetition and the combo will hit 6K with no supers. 7.2K~ with Daisharin 339999 Hatsu Daisharin2 Kokushi Musou
Variation in the corner I mentioned but more difficult to do
5B 2C ItsuuA 6kote Haku Hatsu RiichiA IppatsuA 2 44 (drop and airbackdash under opponent) j.Hatsu Haku Chun 2D late j.C 2C ItsuuA 4kote 3C 2D 6C 6D Daisharin (optional)
Same stipulations as the first combo, can get an extra rep of ItsuuA with 2C starter. I believe damage for this combo is slightly less than the first one I've listed, but again I have no way to test for exact numbers right now.