Deleware Valley White. Great bloomer and good hardiness.

My hands-down favorite is Girard 'Pleasant White', a low-growing, evergreen
variety with quite large white flowers (blooms late). . .it has proven so useful
because of it's low, spreading habit, that there are three of them in my own
gardens, plus several more in friend's gardens in shady, polluted city
habitats, where they thrive!

Carl

Here is a link that might be useful: Missouri Botanical Garden

Both DWW and PW if left unpruned will attain 5-6+' height.
Nevertheless they both are the staples for the northern landscapes because of hardines and ability to bloom even in a fairly shady conditions.
If you intend to keep them low by pruning and width is not a big issue, I'd go with PW because it has more horizontal branching habit, while DWW has a more oval natural shape.
Unpruned 8-9' tall mature DWW are in the back
{{gwi:220213}}

Holy cow that's beautiful. Just in awe.

Now, I knew that Delaware Valley White usually got taller than the 3'-4' that
they advertise in the trade, but, George, you'd better come talk to my three
Pleasant White's (oldest is 8 years) which have NEVER exceeded 2' (as advertised), but have a healthy 3' spread. They may not be living up to their full potential, and just need a pep talk ! :-)

Carl

George you must have great conditions for azaleas! Beautiful! Of course, I'm sure you take very good care of them too. What is it about your garden that they like?