Extending or increasing volume of a quiet doorbell
Many "old analog doorbells" have some old-fashioned mechanical adjustments to alter the volume. If labelled at all, would commonly be something cryptic like a + at one end of a slot, or near a lever, or on the more verbose, a + at one end and a - at the other.

This might allow a longer distance for the striker to move so it hits harder, for instance.

You may also get results from changing or replacing rubber parts, or looking for things like a collection of dust or cobwebs (or eroded rubber parts) damping the chime itself.