https://www.uta-net.com/song/248289/ From this song,
I can't translate " 僕らは目をそらしてはなりたい" and I don't know what's "そらしてはなりたい"
I think you're parsing the clauses incorrectly.
そらして is the te-form of 逸らす (to look away or avoid/change topics)
て-form + は is a conjunction that often means "if/when" but in this case it indicates the repeated actions of 未来の解像度下げ, 目をそらす, and なりたいものなんて無いと嘯(うそぶ)いた.
なりたい is part of the next clause なりたいものなんて無いと嘯(うそぶ)いた日々を. In particular, it modifies もの to mean "something (I/we) want to become".
The phrase 僕らは目をそらしてはなりたい contains the following words:
Hence, the translation of only that particular phrase would be:
We want to avert our gaze
However, if you meant translating the part of the song where that phrase was taken from, then
Dreaming counter my intentions
The sky's four corners, unable to fill my heart's gap
Let's escape this endless night
The future's resolution dropped, we averted our gaze
The days when we bragged about the things we didn't want to be*
For future reference, this site may help with translations.
*This might be wrong, so feel free to correct this one.