I see, I'm not familiar with RPG maker, nor with the concept of pattern tables, so I'm not sure.
But it seems some people have made plugins for RPGM MZ to allow for the use of bitmap fonts.
I found these 2:
https://forums.rpgmakerweb.com/index.php?threads/eli-bitmap-font-use-bitmap-font...
https://decinbr.itch.io/bitmap-font-plugin-for-rpg-maker-mz-easy-to-use
With these you might have to use the sprite atlas (image containing all characters, included in the download folder)