I wanted a front angle you knob lel.
Backing off the intensity
Some of the things you mentioned are straying away from technique and more towards training principles and styles. This discussion would probably go really long if it was to be addressed fully but I’ll ramble a bit to hopefully put you on the right track.
TLDR Testing strength is not necessarily an effective/efficient/sustainable way to build strength. Back off the weight, train reps at lower % 1RM where you can practice and maintain perfect form.
Training with heavy weights and high percentage of 1RM often has both pros and cons.
e.g. harder to accumulate a lot of work when 1x1 @ 95% drains you plenty already in this case it may have been better just to do a 5x5 @ 70%. This way you do more good quality work i.e. the lighter weights allow you to practice and build strength with good technique and positions. When the weight is a struggle to get up all you’re concentration is going into getting it up however you can not on cues and awareness of proper body positions and form. There’s pros also but none really applicable to you at this time.
For you in terms of general training approaches for the deadlift I’m going to recommend something more along the lines of sub maximal training i.e. doing a lot of work at lower percentages where you can practice perfect form with every rep and build up a big base with volume. Also maxing rarely. At most a heavy single and if your form breaks down, feels sloppy or for some reason you are unsatisfied with how it looks you’re done there. Building strength over time not testing often or randomly and expecting to hit a new max every 2 weeks like some noob lifter.
Your max at any one time is determined by numerous factors and often fluctuates throughout a training cycle.
For example something as simple as eating or sleeping poorly the day before a heavy session can decrease performance. Another example would be maxing out all the time and overreaching/overtraining. Another example is that you’ve been building up your volume over time and accumulated training related fatigue. While fatigue is high performance takes a hit but it is necessary at least in the short term because putting in the work to build strength necessitates hard-ish overloading training which generates fatigue. The last example is actually not a bad thing because while you build strength you can’t quite perform as well when maxing but that’s not the point. When you’re done building strength you peak, reduce accumulated fatigue and then you max/test to reveal your true strength that was being masked all along.
Training at lower percentages as per above will probably go a long way towards improving your technique. Patience is also critical because like anything it take practice and with all these cues you need to remember and such it’s easy to get overwhelmed if we cram it in all at once.
Pro tips are to establish a set up routine that you repeat every time you DL. Of course we can try to implement changes to it one at a time but if there’s no existing set up routine it’s hard to gauge how much of a difference is made by the cue alone and not inconsistency overall with technique.
Set up is everything (well maybe more like 90%) so it’s good you are trying to improve it. There are all kinds of set up routines but what’s important is that you end up in an efficient start position. e.g. you can scream, tug on the bar a bit, pump your hips or knees as much as you want but when the bar breaks the floor you’ll need to be in a position where the bar is directly over your midfoot and under your shoulder blades. Where your hips and knees are is determined by your relative limb segment and torso lengths so it’s individual. Finding your start position is mostly practice but maybe these vids can help guide you. There’s some specific methods I like to teach peeps to find hip height but I can’t find the vids rn and it’s hard to explain with words. Might be in one of these vids tho
Important thing is finding what works best for you. Lifters have success with all kinds of squat styles. I think it was mentioned in the vid I linked but it’s also important to be consistent with technique e.g. speed of descent, set up process etc. no matter the percentage of 1RM (within reason of course we don’t want the unloaded bar flying off our backs because we are trying to be explosive).