Bulk editing is simple with Apply to all. Whenever you make an edit that can be applied in bulk, an expandable blue button with checkmarks appears at the bottom of your screen. Tap this button to expand the Apply to all option.
Only your most recent edit is impacted by Apply to all. To use it for multiple edits, select it after each one rather than after several changes.
You can use bulk editing for many features, such as Volume, Speed, Filters, Ken Burns, Text, and others.