Meaning of 〜くらいには and a tricky sentence

Question

I am trying to figure out the meaning of a difficult sentence:

しかしそういう主観に支配されるくらいには、彼女との出会いが気の置けない友達と会うようなものではないことを僕は理解していた

My main issue here is with the expression "くらいには" and what it means in this context. A secondary issue is the word 主観, which seems to mean "subjectivity" in the dictionary, but I am guessing that based on context it is more something like "subjective experience".

My guess at the meaning of this sentence is that he is saying that he understands because he is so compelled/surprised by what is happening (suddenly meeting a previously famous pop star), he is sure that this experience (meeting with her) will not be anything like meeting a friend whom he can speak easily with.

Here is the context in case it matters (middle of 2nd paragraph).

Answer 1

しかしそういう主観に支配されるくらいには、彼女との出会いが気の置けない友達と会うようなものではないことを僕は理解していた

This is a bit roundabout sentence and even native speakers may have to read this twice to get the meaning. The main structure is そういう主観に支配されるくらいには理解していた, which roughly means "I was aware (of something) to the point where I was possessed by such an idea." In other words, "I realized (how special this encounter is) so much, so it was natural that I was possessed by such an idea."

主観 here is just "(subjective) idea/thoughts". In this case this 主観 refers to his unrealistic impression that he has met someone in another world ("beyond the dimension").

What he was aware of is a relatively long noun phrase, 彼女との出会いが気の置けない友達と会うようなものではないこと ("that the encounter with her is nothing like meeting with close friends").

Answer 2

くらいには

くらいには is na-adjective くらい（だ） + particle は.

As na-adjectives exploit nominal particles as their "conjugations", here the くらいに form is treated as its adverbial form (連用形). Also note that くらい itself has both facets as a noun and an adjective. The noun form くらい has adverbial usage, too. However, bare adverbial くらい and くらいに have some difference in usage.

苗が一週間で10cmくらい成長した。 the sapling grew (approx.) 10cm in a week.
苗が一週間で10cmくらいに成長した。 the sapling grew to (approx.) 10cm in a week.

But in all other times when the distinction of the "final level" and the "changed amount" is vague, the difference wouldn't be critical:

もう歩けるくらい回復した。 ≒ もう歩けるくらいに回復した。

Now the second problem is は. It's the well-known topic particle, and particularly in this context, it adds to a nuance of "at minimum". But what might be more important here is that は clearly divides くらい and くらいに into noun and adjective/adverbial usages.

?? もう歩けるくらいは回復した。 (loses the adverbial reading)
○ もう歩けるくらいには回復した。

So, this ～くらいには can be translated as "at minimum to the level/degree —", or in more natural way, "(easily) enough to —". You can never reword it using くらいは.

主観

In philosophical parlance, it should be translated as "subject". The translation "subjectivity" only works in the following definition.

Some information, idea, situation, or physical thing considered true only from the perspective of a subject or subjects. (Wikipedia)

All other meanings of subjectivity (see the link) should correspond to 主観性.

But in daily language, it's used to roughly denote "one's own (personal) feelings/stance/understanding" without much lofty connotation. In this specific case, it indicates the idea that he thinks "僕は今、その次元を超えた邂逅を果たしていた" (in the top of this paragraph).

By the way, the meaning of 支配 is a little hard to grasp. I guess it's intended to be "overwhelm" or "engulf" here. Your "compel" is a good choice too, but in that case "compelled to (have the idea)" is felt more suitable than "compelled by".

The sentence

This sentence is hard to understand correctly. The structure is doubly ambiguous on where the clause ～くらいには should settle on.

1. ～くらいには……理解していた (I was aware ... enough to —)
2. ～くらいには……ではない
   1. ～くらいには……～ようなものだ + ない (it is not [something like ... enough to —])
   2. ～くらいには……～ようなものではない (it is something [not like ...] enough to —)

Though the option 2-1 is less likely from the context, the sentence is still roundabout and ambiguous.

Answer 3

If the sentence was そういう主観に支配されるくらいには…僕は理解していた, your interpretation would be exactly natural.

But what's odd in this expression is that the example sentence actually hires は, which (oddly) implies the protagonist's awareness of how the encounter is not like meeting a close friend is no more than a degree to recognize it as something beyond dimension.

I'm not sure why the author used such an unsettling rhetoric.