You can step a frame backwards and forwards in the sequencer by pressing left and right arrow keys. But if you click on anything that isn’t in the timeline, this hotkey stops working. For example, if you press right arrow to step forward, then adjust a property in the track panel (adding a keyframe or changing a value), and press right arrow again it doesn’t work. You have to click somewhere inside the timeline again for the arrow hotkeys to work again.
Having a universal frame stepping hotkey that works in the sequencer regardless of which window or panel is in focus would be a nice quality of life upgrade for animation. Command and period already does this for stepping to next/previous keyframe.