I finally defeated Armstrong on Hard mode
After 4 days on and off and what felt like under 90 deaths (I lost count of the real number): I got him with a B score. Incidentally on the last day today I had a big panic attack and I felt like I needed a real distraction so after breathing exercises to ground myself I then channeled my emotions into fighting Armstrong. With the last 3 or so tries I muted all the music and sound because I wanted to fully lock in. What I'm saying is Jack is back! I read what attacks would happen and alternate between every type of attack to overwhelm/tire the boss out. Left mouse button, right mouse button spam. Near the end I realised I forgot to press "R" for Ripper mode so I started doing that, it made some but not too significant a difference in this run. Since I regualrly Zandatsu him whenever he was standing up. Even threw in 2 or 3 aerial moves by accident which I had previously wrongly thought Armstrong would always 100% parry air; turns out I needed the right opening or staggering for them to connect. No previous saves were needed, I did this without backtracking.
My 2 health packs just managed to work after I got the 5 health Zandatsu drops. I found 2 forward sword thrusts or 1 of them into left right slashes into the "W" button attacks sometimes cancelled his powerful pyroclastic AOE ground cracks leaving me damage free from that at least forcing him into an attack sequence that I could parry. I also Zandatsu whenever he green healed as best I could and always ran backwards to "F" collect the blade which most of the time felt like a tiny moment of invulerability. If I couldn't make a dodge/slide/run I might as well hit him as much as he hit me during a yellow AOE blast. So yeah The War Still Rages Within; got to play Blade Wolf and Jetstream Sam when I feel up for it. I also wanted to hear Raiden say Revengence with the Konami code but couldn't get it that to work on PC unless that is really only for console versions.