From man systemctl:

##ENVIRONMENT ... ###$SYSTEMD_PAGER Pager to use when --no-pager is not given; overrides $PAGER. Setting this to an empty string or the value "cat" is equivalent to passing --no-pager. ###$SYSTEMD_LESS Override the default options passed to less ("FRSXMK").

So, somewhere in your environment initialization, set:

SYSTEMD_PAGER=

From man systemctl:

ENVIRONMENT
...
   $SYSTEMD_PAGER
       Pager to use when --no-pager is not given; overrides $PAGER.
       Setting this to an empty string or the value "cat" is equivalent to
       passing --no-pager.

   $SYSTEMD_LESS
       Override the default options passed to less ("FRSXMK").

So, somewhere in your environment initialization, set:

SYSTEMD_PAGER=

From man systemctl:

ENVIRONMENT
...
   $SYSTEMD_PAGER
       Pager to use when --no-pager is not given; overrides $PAGER.
       Setting this to an empty string or the value "cat" is equivalent to
       passing --no-pager.

   $SYSTEMD_LESS
       Override the default options passed to less ("FRSXMK").

So, somewhere in your environment initialization, set:

SYSTEMD_PAGER=

From man systemctl:

##ENVIRONMENT ... ###$SYSTEMD_PAGER Pager to use when --no-pager is not given; overrides $PAGER. Setting this to an empty string or the value "cat" is equivalent to passing --no-pager. ###$SYSTEMD_LESS Override the default options passed to less ("FRSXMK").

So, somewhere in your environment initialization, set:

SYSTEMD_PAGER=