would it be possible to add a feature to download carts directly from splore inside pico-8 to a folder in .lexaloffle/pico-8/ that would be configurable in .lexaloffle/pico-8/config.txt in the same manor the carts and save data folders are configurable?

I don't think it's configurable, but carts from splore do download to .lexaloffle/pico-8/bbs/carts on my system.

You can also just escape from Splore and use the "SAVE" on commandline and it'll save the last game you played. I do that often when I find a game I want to dissect.

I’m looking for this to be a handheld console without a keyboard or need to use the command line so thats not really an option

I'm pretty sure carts played in splore on my handheld (RGB30 running ArkOS) also download to the SD card - not sure if the path is offhand, let me boot it up and SSH into it to find out.

EDIT: They just download to the main carts directory, which is /roms2/pico-8/carts.