Lack of Blooms on 6 y.o. Bare Root Trees

I have four Honeycrisp apples.  These were planted from bare root M111 semi-dwarf stock five years ago, Dave Wilson Nursery.  Deer are a constant problem and have been pruning them over the years but they are surviving.  So these trees are 6 to 7 years old.  They are established but only one has ever bloomed.  Maybe got three apples off that tree in 2019.  That's it!  

To pollinate these Honeycrisp I have a Spitzenburg, Empire, Cortland, and Golden Delicious.  The Empire bloomed vociferously last spring 2020 but no fruit ever, and none of the other trees bloomed much at all.  Next year will add two Honeycrisp and a Gala as Empire and Spitzenburg bloom too early for the Honeycrisp, and Golden Delicious is too late.  Cortland hasn't bloomed yet; it's a replacement for a vole dessimated Honeycrisp so only 2 years in the ground.  

So I have Honeycrisp bracketed with pollinators and hoping Gala will be a better match for bloom time.

I have the apples on a drip system - i.e. emitter hose at 1 gph, 12" spacing of emitters - which I run 3 times a week for 4 hours. Idea is to get 12 gallons per week to the plants. This year I set the timer to twice a week and supplemented with hand watering which means flooding to a diameter of 4' once a week or so.  With sporadic flooding, with longer dry spells between, I'm hoping to wean the trees so that they're more likely to survive when I'm gone.

These trees were planted with a mix of a shovel full of azomite, biochar, greensand, bone meal, teaspoon of sulfur and mycrorhyzae, worm compost, and chicken manure to get them started.  Later plantings include gypsum but these apples were the first so didn't think of gypsum. Also sprinkle a little borax every other year or so.  Soil test in 2015 revealed clay loam with 0 boron and 0 sulfur, low phosphorus and potassium, and medium low nitrogen.  Soil is clay and ph 7.0 so I use sulfur every fall and amonium sulfate monthly, 1/2 cup per tree, with last application around August 1 at the latest.  Just sprinkled about 2 cups of 0-10-10 on each tree to get bud development next spring hopefully.  Will start with 0-10-10 application next April 15 or so, with sulfur, then maybe three applications of amonium sulfate 21-0-0 around May 1 and June 1, and July 1 as well.

So it's not a lack of water, soil amendments and nutrients that are effecting the bloom.  Is problem too much water?  Also very late frost and snow this year, so didn't expect any fruit - but it wouldn't matter if I don't get any blooms.

It took me a couple years to realize the ph was probably the problem.  Despite all the nutrients, the trees probably weren't absorbing it because of high ph.  Also used sawdust for mulch for a few years and that probably robbed more nitrogen than I realized.  Trees responded very well to a first application of 21-0-0 in 2018 and have done well since.  The amonium sulfate reduces the ph and stimules growth, about 12" to 24" a season.

Any ideas?  Anything else I could/should be doing?  Surface applications of gypsum annually?  Not a commercial grower.  Location is Sierra Valley, 30 minutes north of Truckee, CA at 5,000 ft. in the Sierra Nevada.

My 2 year in the ground Brambly flowered this year but didn't keep any of the fruit it set, are you getting flower buds? Sometimes they produce the flowers but then fungus or other disease or frost kills the buds before they even open. How big are the trees now? My 2 year old is over 9 ft tall and due it's first prune (the tree is probably about 5 years old but I have had it planted for 2 and in a pot for one before that)
pH 7 is not high it's bang on neutral my soil is 8.5 and I only have 30cm before pure chalk, my apples, pears and plums do not care so alkaline soil is not your problem. Your Empire didn't set fruit as it's only partialy self fertile (some sites say not self fertile) so it will need one of the other trees to get it's act together.

OOH you're using a really high Nitrogen fertiliser, stop that. Yes you will get lots of lovely green soft growth, but you won't get many flowers. to much nitrogen means plants put on growth at expense of flowers. My apple trees get dumped in a hole and that's it, no fertiliser no amendments no water nothing, you may have to water as your climate is very different but I feel you are babying the trees way to much.

Deer browsing has been a severe inhibiter of blooming on my dwarf trees. Few fruiting spurs remain.