I bought a coral bell years ago, now they are coming up all over the place which is great, the foliage is nice, the stems are tall, but there never are any flowers, just what looks like tiny buds. this is frustrating since the plants themselves are doing so well.
You say they are coming up all over which sounds like it is self-seeding but it would have to flower before seeding. Do the buds turn brown before they open? How many years have you not had flowers? Are you giving them too much nitrogen fertilizer? Have you done a soil test of that garden area? Have you examined a flower stem for bugs? Really tiny bugs like spider mites and thrips suck the life out of flower buds and other soft plant parts. If all of these check out, try dividing the plants in fall or early next spring. It may rejuvenate them to divide them. This article gives details on coral bell varieties and which bloom best - there are some that don't bloom well. https://www.chicagobotanic.org/downloads/planteval_notes/no21_coralbells.pdf
This could actually be the type of flower that the variety that you are growing has.
Some varieties have little tiny flowers that almost look like seeds.
Make sure soil is moist, never dry or soggy. Do not over fertilize. Make sure you are growing in shade. Some varieties do very poorly in any sun location.