Pretty sure that one is a Kurume, but the best way to tell the difference is this:
Kurumes bloom first (April), then they grow. Satsukis grow first, then they bloom; in May-June.
That's a definition the Japanese use. But western cultivar that have been cultivated independently may bloom late while only having wild species and kurume in their heritage because they were selected to bloom late. For example, R. nakaharae species blooms later than most satsuki. R.nakaharae has been used quite a bit for hardiness and creeping habit. And wild R.indicum is also used a lot in western hybridizing.
Also, why do you think this azalea blooms first, then grows? Or are you judging based on the leaf shape?
Most azalea bonsai are grown in Japan and are satsuki. They are created from cuttings that are grown into long slender plants which are called 'whips'. You see many tall thin S-shape satsuki. You don't see this in any other kind of bonsai. This plant can't be styled the way whips are styled because it was grown very differently. Often these bonsai have no taper and unimpressive nebari but are ideal for showing off the amazing flowers. Satsuki often have big flowers and those flowers need to be on a big tree. A big flowered azalea that is big and has impressive nebari and taper is extremely rare.
Now all azalea grow back quite easily. You could do an extreme prune. It will often sprout from old wood, but you need to be careful that the old wood doesn't dry out and the sap stream stops.
But indeed, an azalea trunk like this is very rare because garden plants are often deliberately grown in a way that makes them bad for bonsai. But to an azalea the flowers are everything. I dislike filled solid purple or lavender flowers quite a bit compared to other types of flowers. You might have your own preference. How much you like the flowers will affect how high you should value this tree.
Maybe a good idea would be to go azalea shopping late may and buy some garden azaleas. Then you can root some cuttings from the new growth after flowering and grow those into bonsai. But before you really can do some work on those similar to what this tree will require may take too much time.
What you may want to do sooner is to shift to focus of growth away from that one thick branch growing out of the side on the left on the last photo. If it gets even thicker it will cause even more problems to the main trunk. And you probably don't want to cut it below that because then it will be kinda short.