It is nice if you mention what system it is (Sega Saturn in this case), if for no other reason than some systems have fonts built into the BIOS/firmware/some other system level affair and other things have shortcuts that might work for that system. I don't think the Saturn had much here by way of hardware pulled stuff but it is not my main system so I could be wrong (it tending to be very old consoles and early CD consoles that saw this).
What did you try to locate the font?
If leaping immediately to compression I am likely to assume you tried looking at file names and then opening the ROM/ISO up and pressing page down a lot in a tile editor of some form (not sure what we have for the Saturn these days but tileggd and such should still be able to make a version happen).
Such things can work but are far from the whole story, and also tricky for a whole bunch of reasons (custom font size, individual custom character size, various colour depths for characters....).
As well as file names and directory names (to say nothing of elimination -- big folder called sound is probably not going to house the font) you have extensions and file sizes.
Reverse lookup is a thing -- find the font in a tile viewer in an emulator/savestate and search the ROM for that. Compression will get in the way here if it is present (have seen compressed fonts on disc based/high storage systems but they are usually small enough to dodge it) but if it lands in the RAM it might be the same in the ROM.
You say it has sequels so see what went for that and if it applies backwards. Also other Sunsoft or same publisher games from around that time.
Corruption is an option. I get odd looks when I bring it up at times but it works -- if you corrupt a file in a ROM then whatever breaks in the resulting game has to do with that.
After this then yeah time to start looking at assembly -- it will eventually land in video RAM so you get to follow it back up the chain. This is for the GBA and for a command line driven emulator but still the sort of workflow that people will use https://www.romhacking.net/documents/361/
. Afraid I have no clue what debuggers are like for the saturn right now.