Issue appears to be related to display resolution. Grub was booting into 3840x2160 mode, with the resulting tiny, near-unreadable font. So I set GFXMODE=800x600 and now - unexpectedly - kernel 5.2.0 is able to boot without the memory errors.
Not sure why the high resolution causes an out-of-memory error; a 3840x2160x32 framebuffer should only require ~32MB of RAM.
Issue appears to be related to display resolution. Grub was booting into 3840x2160 mode, with the resulting tiny, near-unreadable font. So I set GFXMODE=800x600 and now - unexpectedly - kernel 5.2.0 is able to boot without the memory errors.
Not sure why the high resolution causes an out-of-memory error; a 3840x2160x32 framebuffer should only require ~32MB of RAM.