You can change GRUB and add your own fonts, yes:

   GRUB_GFXMODE=1920x1080
   GRUB_GFXPAYLOAD_LINUX=keep
   GRUB_FONT="/boot/grub/fonts/DejaVuSans30.pcf"

but you can't change the framebuffer resolution:

https://unix.stackexchange.com/questions/201965/setting-the-...

..or at least if you can, no one has bothered to answer my question on how for several years.