Oh actually you’re right. I didn’t interpret the op correctly. I thought it was just some weird extension of Knuth’s up arrow notation but now I see what’s going on.
In that sense, (2) isn’t a real number, as infinity isn’t a real number, it’s an extended real number.
And I think you’re right again, ((2)) isn’t well defined I don’t think.
Edit Edit: It seems I double misinterpreted the parent. I think we’ve agreed that (2) is finite, so if I ramble about it being infinite below, ignore me.
Being “close to infinity” doesn’t really make sense in standard real analysis, if you’re talking about any given finite number, because you can always produce another number arbitrarily larger than whatever you wanted to show was “really close to infinity”.
Edit: So if you’re asking “what’s bigger, the sum of the first billion twin primes, or (2)”, this question doesn’t make sense because (2) isn’t finite, but that sum is.
What’s even more interesting, though, is that you can meaningfully compare different sized infinities. Look into Cardinality.