Hi
I like to suggest that if you set the light level that emits from glow chalk to zero so it just glow like a glow text on signs it would be more vanilla like (it won't interfere with spawning rules in 1.18.2 that requires light level 0) and would solve #13 issue all together.
as you can see in first screenshot it emits light

and this is the lighting bug

thanks in advance
love your work <3

Fixed in 2.0.0

Well, setting the light level to 0 does not make the chalk emissive anymore. But I could reduce the light level down to 1 from 2.
Same issue with vanilla blocks:

Vanilla really does not handle transparent, light emitting blocks well

https://minecraft.fandom.com/wiki/Glow_Ink_Sac#Signs
"Glow ink sacs can be used on signs to make their text brighter in low light levels. This also adds an outline around the text on the sign, the color of which is based on the color of the sign's text. The text does not emit any light, it is only more visible in darkness, similarly to the eyes of Spiders and Endermen."

https://minecraft.fandom.com/wiki/Item_Frame#Glow_Item_Frames
"When an item is placed inside a glow item frame, it appears to glow, even though it does not emit any light."

Well, setting the light level to 0 does not make the chalk emissive anymore.

I meant these two examples that I mentioned above

Ooooh, I understand now. Ty for claring this up.
The text and on Signs and Item Frames are actually rendered very differently from blocks to make them more dynamic as they need to be for storing all kinds of text and items.
Applying this logic to Glow Chalk would give quite a hit to FPS, so I rather not go that route.

now this is why it looks so bad. Come on, vanilla!

Ty very much for the hint! :)

oh I see. thanks for the info
I got that idea from glow banners mod that I have and that doesn't emit light and seems ok to me with the FPS even tho I'm running Minecraft on an old laptop.
also it's open source so you can check that maybe it give you an idea to make it work and if not then I'm happy with current results :D

yeah just to be sure I tested the performance for FPS

with this many glow banners my FPS didn't change after and before adding glow ink to banners.
I hope this info helps.

The text and on Signs and Item Frames are actually rendered very differently from blocks to make them more dynamic as they need to be for storing all kinds of text and items.

Also I asked one of my friends that is a modder and he said item frames are entities and entities effects FPS but glowing effect has nothing to do with performance. since entities need to be rendered differently like a mob or armor stand and has a hit on performance.

@DaFuqs
Bigger sample size
Before

After

The glow effect doesn't affect performance in this case.

@DaFuqs any news on this issue? or should I create it again?

I tried it out in the current snapshots again, but it seems the lighting issues in vanilla with mushrooms and all seem unchanged, sadly.