Definitely, repertoire is the key. It has two distinct advantages over new gear… For starters, it’s free! You need to blow a few thousand on a new arranger. But you can either figure out a song yourself (the best way to learn), you can usually find a free chord chart online if you can figure the melody, sometimes you can find a free chart (these can be a bit hit or miss if you’re after the ‘correct’ changes). Push comes to shove, you can put a few dollars into buying the actual chart.
Then for a few tens of dollars, there are legal fake books in most genres. Hundreds of well known tunes.
You’re going to make huge steps forward learning new tunes, new chord alternatives (a lot of jazz fake books will offer alternate chords to sections, which will help you learn new ways to play standard changes). A new arranger playing the same tunes won’t help YOU progress, just sound a bit different….
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An arranger is just a tool. What matters is what you build with it..!