I'm trying to open my radio and my screwdriver is not narrow enough to reach the screw.
This problem occurs often with multi-tools type of drivers having many short replacement bits.
While there are bits with slightly longer shafts, they are expensive. They would cost more than another single-purpose "normal" screw driver of the proper type. Also, they won't fit inside your bit storage area.
If you have a "needle-nose" (thin, pointy one) pliers, you could possibly grip the end of the bit to allow enough of the tip of it to reach the screw head.
If you have a "slot" screw driver with enough length, you can use it to reach the star-shaped screw in your radio.
If you only need a little more length, don't push the bit so deep into the shaft of the multi-tool. Let it stick out a bit more since you only want to twist the screw. If you have anything that is "loose fitting" but "not magnetic" you can put it into the multi-tool shaft as a spacer. (Warning: Pick something that will not get stuck in the multi-tool shaft. Avoid metal foil since it will be difficult to remove if it gets compressed inside the multitool shaft.) A small plastic bead or two might work to extend the length of the tip to reach the screw.