You have a host of problems the major one being Algae.
Your secondary one is old leaf loss in Ludwigia(?).
You are too focussed on ferts, yes you don't need 'Classic EI' or anything close to that level of dosing, but you have to deal with Algae first.
I would start with good husbandry. Scrub glass, take out all stone and scrub it. Remove the worst algae infested leaves/plants and then do 3X 50% water changes in succession to reset things as best you can.
Then I would stop dosing for a week, lower light duration to 4 hours/day and see if your tank adjusts and algae stops growing.
I would do that first before considering any other changes. The substrate may be loaded with ferts and this excess may take a long time to deplete so I wouldn't worry about dosing for a while. Even afterwards with your hard water I would favor Osmocote plus sparingly near hungry stems over caking on ferts in the water column.
I suppose I could try this as I have nothing else to lose. It doesn't necessarily help me understand what has been going wrong though. My best guess right now is that EI is causing all of the issues because my tank isn't planted heavily.
Also, I've been performing your suggested cleaning and husbandry for months now. What you see is what I get after 5 days after cleaning with the current setup and plant mass.