From the video, which as I said may be giving an inaccurate impression of the bicycle speed, it would seem that DHD approached the situation far too fast.
That's easy to say after the fact, as a collision occurred. However, was it unreasonably fast? I don't think it looked like it. Maybe
@dhd.evans has a GPX recording and can clarify the last speed recording before the incident.
There are no lanes, the driver has not crossed into the wrong lane as it is a single lane road. The driver has just passed a parked car on their nearside and is now ready to turn right. This is similar to the frequently given advice on this forum to 'take the lane' or use a 'strong primary position'. Having effectively blocked the road to oncoming traffic it is then unfortunate that a cyclist travelling at speed comes along and decides to squeeze through the remaining gap.
You say "decides to squeeze through the remaining gap", I'd say "was left with nowhere else to go". It's a tough call: on first viewing, I thought in that situation I might attempt an
emergency turn (USA site, so see "turning left" for a situation like this right-cross), but on seeing the close examination of the road later in the video, it loosituationks like it may have been too wet for that and could have resulted in a low-side skid/crash leaving the rider on the road in front of the unobservant motorist's vehicle, which could have been much worse.
If the motorist thought they had "effectively blocked the road to oncoming traffic" then they failed to remember two-wheeled oncoming traffic and may have proceeded without looking properly.
I accept that the driver could have done better, but they certainly were not reckless.
I think that's far from certain (reckless = "it would be obvious to a competent and careful driver that driving in that way would be dangerous"), but even if so, were they careless ("the way he drives falls below what would be expected of a competent and careful driver")?
The OP's safety is not just the responsibility of others. He must assume some of that responsibility himself. Coming round a bend and rushing headlong into that situation regardless is a recipe for disaster, which on this occasion it was.
That's still assuming "rushing".
Also, let's compare with a similar everyday situation: when did you ever see a motorist proceeding straight ahead through a T on a priority route (as you put it earlier) "aim for a gap that is [narrower than 3x their vehicle's] width without considering the [oncoming] vehicles intended actions and without slowing to check if [they] are actually seen by the driver and it is safe for [them] to proceed"? That's almost every motorist on almost every road, isn't it?
Too many on this forum have a 'driver bad, cyclist good' mantra but this is wrong and unfair, not all drivers are bad and not all cyclists are perfect. Both parties could have done better, which is why I suggest the responsibility is, at best, 50:50.
I suggest that's far too harsh for the reasons above - and I feel that far too many on this forum have a personal-responsibility/"only crap cyclists crash" mantra, which is also wrong and unfair. Calling this 50:50 just because both parties might have maybe been able to do things differently seems unreal to me: one vehicle was proceeding straight ahead along the priority route and its rider seemed to grab handfuls of brake as soon as they saw what was happening, while the other was turning across its path and its driver apparently failed to react before the collision. The burden is clearly on the road user turning across a priority flow. Even at worst, this should be nearer 80:20 against the driver IMO.