Using loader.conf(5) 'exec' directive to set video mode

I'm running (a somewhat dated) FreeBSD 13.0-CURRENT (git commit 
68c8581f7, Tue. Feb 12 13:01:55 2019) on a UEFI laptop with an Intel UHD 
display, booting a ZFS root filesystem (gptzfsboot(8)). I'm trying to 
get the console into a lower resolution than the native UHD when the 
kernel is booted.  I can manually do this by breaking into the loader 
prompt at boot and entering 'mode 1', then 'boot'. loader.conf(5) says I 
can run this command automatically with the 'exec' directive, but the 
video mode doesn't change.

$ sudo cat /boot/loader.conf
Password:
autoboot_delay="3"
#boot_single="YES"
boot_verbose="YES"
kern.timecounter.hardware="HPET"
hw.psm.synaptics_support="1"
kern.vty="vt"
hw.vga.textmode="1"
efi_max_resolution="1920x1080"
exec="mode 1"

I've also tried using directive 'efi_max_resolution' - same result. Does 
'exec' work on my configuration (UEFI boot, ZFS root), or am I not using 
it right?  I've tried putting other loader commands in 'exec' with no 
effect. Same question for efi_max_resolution.

A separate question (possibly for graphics_at_ or x11_at_) is when the i915(4) 
kernel module from the graphics/drm-current-kmod port is loaded by 
rc.conf(4)'s 'kld_list' variable.  When I do manually set the console 
resolution using 'mode 1', it is reset to maximum resolution when 
i915(4) is loaded.

Thanks in advance,
Anthony Jenkins