指示代名詞が多すぎて、正直、わかりづらいことこの上ない。

、、。

With so many demonstrative pronouns, honestly, it couldn't be harder to follow.

Literal

Demonstrative-pronouns [subject-が] too-many-[te-reason-くて], honestly, hard-to-understand [thing-こと][nothing-beyond-この上ない].

~ことこの上ない is a fixed emphatic pattern literally 'nothing surpasses this X,' meaning 'nothing could be more X, X in the extreme.' Used with adjectives or noun+な to mean 'maximally X.' 指示代名詞 ('demonstrative pronouns' — これ, それ, あれ etc.) ~づらい ('hard to X') attaches to verb stems for 'difficult to do.'