The interlinear Grk. feature to my Bible software helps with interpretation, digging deeper for original meaning. The syntax is helpful though I have no formal training here!
In verse 44, the reference to "the" Holy Spirit in Strong's (G3588. ὁ ho) appears twice, where in verse 45 "the" Holy Spirit" is found only once. Not to mention Acts 5:32. All are definite article.
Dr. Zodhiates lays out that which I believe is fundamental to the question: the noun pneúma. He applies his ordinal numbers, which in most references I will apply # I - Spirit as "Breath," though in the above, it seems #III (1) (B) is where our Apostle is going. Yet, how are we to handle this # III ordinal number?
( Strong’s Greek #4151 pneúma…noun from pnéō (4154), to breathe. The following is abridged
**(A) Of the mouth or nostrils, a breathing, blast**
(A) The vital spirit or life, the principle of life residing in man. The breath breathed by God into man and again returning to God, the spiritual entity in man (B) The rational spirit, mind, element of life. (1) Generally, spirit distinct from the body and soul.
(III) A spirit; a simple, incorporeal, immaterial being
(A) Spoken of created spirits: (1) Of the human soul or spirit, after its departure from the body (2) Of an evil spirit, demon…” **(B) Of God in reference to His incorporeality** **(C) Of Christ in His exalted spiritual nature,** His nature as true and proper God
Zodhiates, S. (2000). The complete word study dictionary: New Testament (electronic ed.). Chattanooga, TN: AMG Publishers. )