You can show the individual finger controls through the rigify UI, the manual says how to make it appear. In case it doesn't work (probably in blender 4.0+) just select the metarig from the objects list and look for the option to update metarig, after that use the option re-generate rig.
If it's too complicatyed don't worry soon I'll add 4.0 versions so people don't need to do this step.