Batman has contingency plans for himself as well, such as the Failsafe and Tower of Babel protocols, which he can use to take down the Justice League if necessary.

Source: https://screenrant.com/15-best-anti-justice-league-weapons-batman-has-only-used-once/

Failsafe literally chased Batman to the moon and back to fulfill its programming, which it did when it shot Bruce with a gun that sent him to another universe.

Source: https://screenrant.com/batman-zur-en-arrh-failsafe-body/

Robin knows that Bruce was exhausted mentally and physically when he fought Failsafe.

Source: https://screenrant.com/robin-new-costume-batman-multiverse-rescue-signal/