Any chance of posting images?

This photo of split bud is typical all over large bush

That's not a split bud. It's a cluster of new vegetative shoots which will become new branches.

I don't know what you mean by "radical pruning," but if excess wood is removed, then the plant won't bloom for a year or more until it replaces some of the missing wood. I suspect that's why you don't have any flower buds.

Too much fertilizer and not enough sun light will cause a plant to just form these foliage buds and not produce flower buds. Flower buds swell to the size of a golf ball before they open. These are foliage buds.

Here is a link that might be useful: How to grow rhododendrons and azaleas