Analysing the key by software will sometimes be imperfect unless the song is a fairly straightforward, e.g., 4-5-1 or 6-4-5-1. Jazz notably tends to shift key-centres throughout a song. Other music sometimes also does so that, though generally less often. If the key-centre keeps changing then some, possibly arbitrary, decision needs to be made about the choice of key.

Some people have a philosophy where everything is written with a C/Am key signature and all accidentals are applied to each note as needed.

Jazz relative beginner, starting at a much older age than was helpful.
AVL:MXE Linux; Windows 11
BIAB2025 Audiophile, a bunch of other software.
Kawai MP6, Ui24R, Focusrite Saffire Pro40 and Scarletts
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