Im happy about the final result so here's a little tutorial to achieve this result or explore this subject :
1 - First a quick reminder
fXXX.iff = floor id
sXXX.iff = arena id
XXX is the team ID
you can find the main Stadiums/Floors IDs in this 2K20 topic
Also note that on 2K16~23 you can open/extract IFF files with 7-zip
2 - modded arena lighting
i'm a lazy man, so when I started to tweak lighting at small level after reading Bongo88's guide : i used to only pick postfx and crowdfx files from the arenas which had the best lighting.
It can gives a good result on 2k17~23, but on 2K16 its not enough.
Thanx to rtomb, he mentionned lately IBL lighting in a 2K23 thread
it reminded me that 2K16 has IBL files (btw on recent games, those IBL files have GRU_ as prefix, or AWAY/HOME_IBL on 2K19)
So, still as lazy i can be, i cherry picked all those files from the arena/s which has/ve the best lighting, and copy them into the destination arena.
i packed those files, you just have to add them into any arena files.
3 - modded floor lightmap
Another modification (a real one this time) i made, is to create my own floor lightmap, trying to add shadows to the hardwood floor.
on 2K19~23, 2K separated this lightmap in a specific iff fille sXXX_floor_lightmap.iff
on 2k16/17 the lightmap isnt aside, but directly in fXXX.iff
the texture is LightmapTextureBC3#various_chars.dds depending the modded floor you use
Note that i had to make it in Photoshop to keep the alpha channel
ps : this lightmap dds file is called by floor.SCNE ; if you have any black floor texture issue, open it with notepad++, look for the dds texture and remove the line "Format": "BC3_UNORM",
Modded lightmap texture file is attached to this post. with 2K16 floor.
The floor texture is mostly empty with only pink sidelines as visual marker if you want to mod floors.
4 - modded floor texture added
The final little touch is the court texture.
Nothing special here if you know how to create a floor texture, except that i discovered lately that working with a TIFF file gives a more realistic result (colors are less vibrant)
I create my floors with PAINT.NET (its so much quicker for me), so i save it as BMP.
Optional : I use the software Gigapixel AI to upscale the floor (with a factor of 6) to improve the quality. AI Gigapixel generates a TIFF file.
I open this file it into Photoshop, i select the 3rd option "remove the embedded profile" (im not sure of the translation), resize it down a little bit
then export to DDS with intel plugin.
