Why not use it for font storage?
Because this thread will be followed with "how can I speed up my OLED display routines?".

The choice is obviously yours, but the 18F27Q43 has 128K of flash, 8K of ram, and runs at 64MHz.
The only downside is the hardware I2C peripheral isn't compatible with the old MSSP I2C, so you're stuck using PBP's software I2CWRITE/I2CREAD or rolling your own (which is not trivial for these new parts).