。
She wanted to live a more relaxed life.
Literal
[topic-は] more relaxed-した life [object-を] do-wanted.
生活をしたかった unpacks as 生活 ('lifestyle, daily life') + を + する ('do, lead [a life]') + ~たい ('want to') + past — 'wanted to lead [such a life].' Japanese expresses 'living a [type of] life' with 生活をする rather than a single verb 'to live.' The mimetic のんびり ('leisurely, unhurried') paired with したい patterns commonly express the idle, unrushed life many learners encounter in daydream contexts — まったり (mellow), ゆったり (roomy), ゆっくり (slow) all live in the same family.