mcfunction working well on player inventory but not in container

Hi,
i'm kinda new in the making of datapacks in Minecraft 1.20 and I've got an issue with the GUI i'm trying to make.
I'm trying to set an item inside my chest_minecart with the glint effect when the predicate is met, this work well using my player inventory ans container using the '/function' command but not in the minecart
so far i have this:
execute as @s if predicate custom_gui:has_dye run item replace entity @s container.14 with fishing_rod{display:{Name:'{"text":"fisherman","color":"yellow","bold":true}',Lore:['{"text":"", "color":"blue"}']},objd:{gui:1b},Enchantments:[{}]}
execute as @s unless predicate custom_gui:has_dye run item replace entity @s container.14 with fishing_rod{display:{Name:'{"text":"fisherman","color":"yellow","bold":true}',Lore:['{"text":"", "color":"blue"}']},objd:{gui:1b}}

I don't know a proper way to test effectively either, some tips about that would gladly help.
Thanks !