That’s a big gap and a nice fix. I have a 2017.5 16BHS and have just the rounded corner 1/8 gap in the front there. Cannot see past the flooring at all. I did recently fill that area with clear flexible silicon.
I had ants under the water heater, so filled silicon where ever I could find possible entrances (the propane line went through a hole I could see light through). Filled that hole (from the top and underneath) as well as that crevasse in the front floor storage area.