I don’t think the spell targets the caster at all: it creates a weapon. The only time a target is mentioned is in making an attack (presumably against a different creature).
“You weave together threads of shadow to create a sword of solidified gloom in your hand. This magic sword lasts until the spell ends. It counts as a simple melee weapon with which you are proficient. It deals 2d8 psychic damage on a hit and has the finesse, light, and thrown properties (range 20/60). In addition, when you use the sword to attack a target that is in dim light or darkness, you make the attack roll with advantage.
If you drop the weapon or throw it, it dissipates at the end of the turn. Thereafter, while the spell persists, you can use a bonus action to cause the sword to reappear in your hand.”
Rereading this now just adds to the uniqueness of this situation. The bolded line is very interesting: even when the sword “dissipates”, it still exists, as it lasts until the spell ends.
Flame Blade is similar in some ways, but doesn’t actually create an object: it just evokes a flame in the shape of a blade.
Just to reiterate: “Range: Self” is not targeting the caster: Eyebite, Detect Thoughts, Fear, etc, all target others. It really is just setting a starting point for the range. For SB the sword is created on your person, but clearly it effects others
I will say that it being Illusion rather than Conjuration is interesting. By rule, it seems, Illusions target others: “Illusion spells deceive the senses or minds of others. They cause people to see things that are not there, to miss things that are there, to hear phantom noises, or to remember things that never happened. Some illusions create phantom images that any creature can see, but the most insidious illusions plant an image directly in the mind of a creature.”
Great question. I’d lean towards “no” as DM would dispel the effect on the target, which would mean the spell ends on the target, and so the below contingent RAW from Hex wouldn’t ever occur:
“If the target drops to 0 hit points before this spell ends, you can use a bonus action on a subsequent turn of yours to curse a new creature.”
That is, the spell ending on the target means the target wouldn’t ever drop to 0 hit points before the spell ends.
However, I’d go the other way for Telekinesis as it states:
“You gain the ability to move or manipulate creatures or objects by thought.”
So the ongoing effect is clearly on the caster (the “you” in the RAW). There would be another magical effect restraining the creature target or lifting the object target, which could be dispelled, but the caster would still maintain their magical effect, which is the spell.
If it matters to you, Safe Advice Compendium answered this:
“If dispel magic targets the magical effect from bless cast by a cleric, does it remove the effect on all the targets? Dispel magic ends a spell on one target. It doesn’t end the same spell on other targets.”
This also heavily suggests what I thought was commonly accepted that you can’t dispel Concentration. That is, if Priestly included himself in Bless, and he is affected by DM, the Bless would continue on the other two targets, even though DM was cast on Priestly