I will start by saying that I had not considered berteroi, I don't recall ever seeing it for sale around here, and had to look it up.
It still sounds like it is too big of a plant for my tastes in an aquarium this size, 12" (assuming width as well as height) in an aquarium that is < 15" front to back (from memory) still would be too overpowering for my tastes, and then the spread of the roots and ever wanting to remove it can get messy, especially with a capped dirt substrate.
And yes, the emersed form of the plant will be different, bigger in your case, from submerged, the big difference is that outside of the water the pieces of the plant, leaf stem etc.) Need to be so much bigger or thicker to support the weight of the plant without the water. You will also see different growth based on the length of the photoperiod as plants will transition to it from winter growth based on this and you will normally get better and bigger plant growth if you leave the lights on for more than 8 or 10 hours (and control algae by having less light intensity or simply dimming them)
And I wish I knew more about aquatic plants here in PA. I had to turn down a trip to Florida hunting for plants just before Covid, and need my health to be better before I go out anywhere else.. but it's absolutely on my bucket list if things to do. At least in the continental US anyway.