Edit /efi/loader/loader.conf and change the value for console-mode
The possible values are:
console-mode
This option configures the resolution of the console. Takes a number or one of the special values listed below. The following values may be used:
0
Standard UEFI 80x25 mode
1
80x50 mode, not supported by all devices
2
the first non-standard mode provided by the device firmware, if any
auto
Pick a suitable mode automatically using heuristics
max
Pick the highest-numbered available mode
keep
Keep the mode selected by firmware (the default)
I would try setting it to max and see if that gets you what you want.
After changing that file, nothing else is needed. You can reboot to test after that.