The biggest issue, in my mind, with producing these boards for TFT is the alignment of megahexes.
The second (again, in my mind) is how few 1.5" megahexes fit on an 8.5x11 sheet of paper, if one is to print, glue & cut chambers themselves.
GloomHaven uses 1.25" hexes without megahexes, making things simpler.
I've noodled over how to make my own boards with 1.5" MegaHexes and gave up.
If you have access to a 3D printer, Thingiverse has a set of 3D printable hex boards for GloomHaven, and one specifically that allows you to create your own - with magnets so everything sticks together. Shockingly, it's called
MagHex. The designer has half hexes that would allow creation of square rooms, as well as walls and doors.
I'm just printing the last upgrades to my printer for now (yes, one odd part of the 3D printing hobby is printing upgrades to your printer), have to make another pass at tuning up my bases for TFT so minis fit tighter, and then I'm going to start printing these, and possibly remix them into rectangular corridors/rooms.