sudo/doas does not give the expected permissions when using an eshell alias:

When no alias has been defined:

~ $ which cp
eshell/cp is a native-compiled Lisp function in ‘em-unix.el’.
~ $ touch test
~ $ cp test /boot/efi/
Opening output file: Permission denied, /boot/efi/test
~ $ sudo cp test /boot/efi/
~ $ echo $?
0

But after defining the alias:

~ $ alias cp '*cp $*'
~ $ which cp
cp is an alias, defined as "*cp $*"
~ $ sudo cp test /boot/efi/
/usr/bin/cp: cannot stat '/boot/efi/test': Permission denied

I have attached a patch with a possible fix.