Moreover, a desire to do something is different from a state of being.
Wag you are putting your preferred meaning of the word soul in the mouth of Mary ....
psychē = Soul
1) breath
a) the breath of life
1) the vital force which animates the body and shows itself in breathing
a) of animals
b) of men
b) life
c) that in which there is life
1) a living being, a living soul
2) the soul
a) the seat of the feelings, desires, affections, aversions (our heart, soul etc.)
b) the (human) soul in so far as it is constituted that by the right use of the aids offered it by God it can attain its highest end and secure eternal blessedness, the soul regarded as a moral being designed for everlasting life
c) the soul as an essence which differs from the body and is not dissolved by death (distinguished from other parts of the body)
Her soul, her breath,her very life, all my feelings etc..magnifed the Lord
megalynō =magnify
1) to make great, magnify
a) metaph. to make conspicuous
2) to deem or declare great
a) to esteem highly, to extol, laud, celebrate
3) to get glory and praise
Mary does not say or imply she is sinless , in fact very much the opposite
Luk 1:47 And my spirit hath rejoiced in God my Saviour.
Wag do you believe that mary really never sinned, that she kept all the law perfectly ?