Metallic sound in instrumental after separation

I used PopPop AI to separate the instrumental and vocal tracks of a song that was created by Suno AI.
I’m definitely a novice, so I don’t know what function I would use to try to reduce this metallic sound, which only occurs in parts of the instrumental track. I would also need to know how to use whatever function might be able to correct this.
Also, does anyone know of a tool that would improve the overall quality of instrumental tracks created by AI? I’ve tried using the Bandlab Mastering tool, but it doesn’t do much.
Thank you - I appreciate everyone who takes the time to assist!

Spectral editing to nitpick out the offending frequencies, (very slow but precise) ,
or sacrifice all of the treble with low-pass 1700Hz 48db/octave filter. (quick).