Sound Check inconsistent with local files, any fix?

Why does Sound Check barely affect local files? I want all my music to be relatively the same volume, and it works fine with songs on streaming for the most part. But with local files it barely does anything, sometimes there is no change at all when I switch it on. As a result, 90% of my local files are louder than the streaming songs. Wondering why this happens, because there is no way Apple uses the same method on both streaming songs and local files. The files i’m using are imported via the iCloud library on my phone and are mostly normalized. If there is any way to fix this I would like to know, but I wish Apple just used the same method for both LF and streaming. Hope to see that fixed in the future