Isn't it shirk to seek refuge in the perfect words of Allah?

You are asking Allah for xyz by virtue of his names. You are not addressing his names. You are addressing Allah

Further explanation here : https://islamqa.info/en/answers/185053/ruling-on-a-person-saying-o-wisdom-of-allah-or-o-mercy-of-allah

No. Why would it be Shirk? - The perfect words of Allah (ﷻ) are not a creation; they are His uncreated word and they are of Him. Therefore, seeking refuge in His Word is fine.

Khaula bint Hakim Sulamiyya reported:

I heard Allah's Messenger (ﷺ) as saying: When anyone lands at a place, and then says:" I seek refuge in the Perfect Word of Allah from the evil of what He has created," nothing would harm him until he marches from that stopping place. (Sahih Muslim 2708)

Prophet Muhammad (ﷺ) is the one who taught this to us; would he teach other than Tawheed? SubhanAllah. No; nor is there any person who understood Tawheed better than he did. So there should be no doubt.

*Future reference: You may refer to scholarly Books on Tawheed. They do cover this hadith.