there's nothing intrinsically wrong with having "thereby" there, if it's justified by something in the modifier(s).
for an analogous example, consider the use of "also" in the correct answer to this one:
https://www.manhattanprep.com/gmat/foru ... t3170.htmlin that sentence ^^ you need the content of the modifiers for "also" to make sense—but that's ok, because the modifiers are there. (:
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in any case, it should be clear enough that the two colored parts are non-parallel; there's no reason to over-think this.
that yellow... my eyes!