If you just need to get data out of an iPhone backup — messages, photos, contacts, call history — OpenExtract does that part, for free, with source code you can read.
iMazing is a good tool. It's also paid software, closed source, and Windows-and-Mac only. If the only reason you're looking at it is to pull data out of an iPhone backup, you don't need the whole suite. You need an extractor.
That's what OpenExtract is. Nothing else — no music sync, no app management, no live device browsing. Just: point it at a backup, get the data out.
Being honest: if you need more than extraction, iMazing still has advantages.
See the full comparison for the complete feature matrix.
Install OpenExtract, point it at your existing backup folder, done. You don't need to re-back-up your iPhone or uninstall iMazing.