After that step, the phase proceeds to the end of combat step. The only creatures that assign combat damage in that step are the remaining attackers and blockers that had neither first strike nor double strike as the first combat damage step began, as well as the remaining attackers and blockers that currently have double strike. After that step, instead of proceeding to the end of combat step, the phase gets a second combat damage step.
702.4b If at least one attacking or blocking creature has first strike (see rule 702.7) or double strike as the combat damage step begins, the only creatures that assign combat damage in that step are those with first strike or double strike.702.4a Double strike is a static ability that modifies the rules for the combat damage step.From the Comprehensive Rules (April 14, 2023- March of the Machine)