Those curds look just about right to me. I've used both high temp pasteurised milk (75 C for 15 seconds) and low temp (63 C for 30 min). Granted the latter was non-homogenised as well. The high temp curds are definitely a bit softer, but I wouldn't say that they are a *lot* softer. I lack experience, but I didn't really feel I was overly hampered by the curds.
I would say that in my experience, for the first 5 minutes of stirring, the curds are *very* soft. For example, it takes no effort at all to cut them with the metal spoon I use and inevitably many get cut just through the act of stirring. So my goal for those 5 minutes are simply to stop them from matting at the bottom. By about 15 minutes of stirring, they are setting up and I can grab one and feel some resistance between my fingers. It takes at least 30 minutes more (say 50 minutes after cutting) for the curds to be a consistent texture throughout. But that depends a lot on the temperature of the vat and how fast the flocc time was.
Now, 6 minute flocc time is *very* fast. The fastest flocc time I've had was 8 minutes and that was with a thermophilic starter at 42 degrees that had acidified for an hour. I could feel the curd hardening *as I cut it*. So I wonder... perhaps your idea of flocc time is different than others. I know I had some problem with that at first.
Flocculation is the time when the milk starts to coagulate. So my initial thought was as soon as I see it coagulating, then it is flocculating. This is probably technically true. However, I realised that when people are referring to "flocc time" with a multiplier, they are looking at a different point -- it's the point where the milk has coagulated enough that a floating plastic tub can no longer rotate. The trick here is that when that happens depends heavily on the mass of the tub. Something that is more massive (think heavier) will have more momentum than something that is less massive (think lighter).
So I confused myself a couple of times. Originally I used a fairly large tub (say 5 cm across). Then I used a cap from a milk jug. Of course the cap seemed to show flocc time earlier, because it's less massive and requires less gelling to get it to stop rotating. So the technique is hard to communicate between different people. However, if you always use the same technique with the same item, then you can adjust your multiplier to match (generally speaking).
To make it a bit easier to relate, for the scale that people are generally talking about, at 1.6x the flocc time, the curds can be cut, but are super messy. For you that means that if your 6 min flocc time is the same as other people's flocc time, then at about 9 and a half minutes, you will be able to cut the curds and see the cut. At 2x the flocc time, you cut the curds and it's pretty clean, but white fat oozes into the cut. So that would be 12 minutes for you. At 3x the flocc time, you cut the curds and only clear whey goes into the cut (18 minutes for you). At 3.5x the flocc time (21 minutes), it's basically bouncy castle time. You can press down on the surface of the curds and it will separate from the side of the pot without splitting. (Note: times are based on my limited experience and what I've seen in various Youtube videos... I'd love to get feedback from others who have different experiences). Some people don't call it as flocculated unless when you remove the tub, an impression in the milk is left. This usually happens quite a bit later for me, so even these may be incorrect.
What's likely is that the same thing that happened to me, happened to you. Your 6 minute flocc time was actually about 15-18 minute flocc time and your 45 minute curd cutting is about 2.5-3x flocc time. But again, it really doesn't matter as long as it's consistent. If you can measure your flocc time as 6 minutes and your cut time is 8x flocc time, that's absolutely fine as long as it never changes.
