Is "Scaler" a software to find solutions for problems like this?
You bet it is.
BIAB also has a solution for problems like this.
With a quick setup, the Song Form Medley Maker creates a Chord Sheet with BIAB generated Transitions that's similar in concept to the familiar Generate Chords for Intro feature. Thus, transitions can be regenerated repeatedly until a satisfactory sound is found.
The Medley Maker also allows the order of chord progression sections of the various keys to be rearranged for more possible transition possibilities. Other settings that can be changed includes the style, tempo, key, start bar, # of bars and the number of transition bars.
From the BIAB Help file: (The) "transition bars are automatic generated bars of chords inserted by BIAB to transition from one song to the other, generating an "outro" and "intro" between songs."
The setup involves saving each chord progression section of the song as its own distinct SGU file to be used to create a medley with transitions. In my example image below, I broke up the original Chord Chart into 3 sections.
Then, in the Song Form Medley Maker, each section can be appended to the Medley in any order desired, a transition from 0-16 bars can be designated between the sections and a custom SGU Chord Chart created to play the medley as a single song.
Note the title in the attached image adjusts the Song Title to reflect the order and unique name of the saved sections.