i find if your questioning something its mostly true either your too fatigued or weights not increasing therefor giving you the stall effect of gains.
i'm not a fan of high volume anymore it comes a time were people think they are at failure but they are just fatigued from high reps and volume generally not beating last sessions lifts.
and moving blood around at high reps i dont count as progressing just chasing the pump.
lower the volume to increase the intensity "more weight"
use a log book they dont lie or forget. once your beating it body composition follows.
I think it is smart to do both, using them in different mesocycles.
I did Mike Israetel's RPE volume method for my last bulk, where you start off lowest volume possible, like 2 sets per exercises, twice a week, and increase the volume each week by 1 extra set, until you reach week 6 of you max volume. To find your max volume, you have to experiment and figure it out, since everyone is different.
From week 1-6, you're also increasing how close you get to failure, starting at 3 reps away week 1, up to zero reps away at week six. The final weeks (5-6), you are going HAM and basically overreaching, then you deload for a week.
When I do my HIT method, I do as many warm ups as I need, and then I go do my two sets to failure. I don't go beyond, because the second set to technical failure acts to make up for the one I can't go beyond. I use FitNotes to keep track of my workouts and progress with reps. But I would still be doing PPLPPL, so my volume is super low, but frequency is high.
I found in the end, both achieve the same results for me, but the volume training is "easier" on my joints and does provide a better pump, whereas HIT I can see progress literally every 1-2 weeks.
Interestingly enough, when I got off my cycle and did HIT method for a six-week meso, I got my strongest while not being on. Sure, the drugs weren't completely clear of my system, but you get my point.
So really, I think it comes down to preference. How do you like to train? If you don't have time and want to push to the max, in order to know you went all in, then HIT is great. But if you know your body and how far you are from true failure, then I think volume with RIR training is "safer" in the long run, especially for us older guys; I'm 38 and I've never been injured, and I'm not trying to get injured anytime soon.
That's not to say HIT isn't safe, because it can be, but you can't be doing DORIAN style indefinitely; as he said himself, he regretted going beyond failure all year round even in prep, which lead to his injuries. I think cycling between styles probably gives everyone the best of both worlds.