For others that might find this searching one day. The Gameboy/Gameboy color are somewhat like the NES but rather than mappers it is memory bank controllers aka MBCs that allow the cartridges to exceed the limits of a basic 8 bit system and sometimes add a bit more hardware to it. Swapping in and out sections of the cartridge such that it is not all visible/accessible at once tending to be how that goes down. https://bgb.bircd.org/pandocs.htm#memorybankcontrollers
for a basic breakdown of known ones (though there are some more exotic options, rare examples and user made ones these days that you probably will not care about). You can change the MBC type a game uses but it is also not necessarily a trivial hack like expanding a GBA or DS game might be.
Anyway the pointers might be 2 byte but what is the encoding? Might it be suitable for an 8 bit text encoding change? (16bit is rare on the GB/GBC but not unheard of).
The code handling the text pointers will generally want to read said pointers and the GB/GBC does not have enough RAM to be stashing a pointer list in RAM and leaving it there (though it is a possibility).
To that end if you know where the pointers are then it should be a matter of setting a break on read to that location (as in the where the pointer is at, not where it is pointing to) and going back before that text is ever likely to have been loaded/generated. It will then pop up saying something read this and you should then
If it is one of the strange for GB/GBC games that grabs the pointer table to languish in RAM then you do the same but set your break on read to that RAM location (if it is not a copy of the pointer table as it was in the ROM then you can work backwards from it grabbing the text data from ROM) and then watching it do its maths and thinking through how you might subvert it to read another bank or something.