How to recover albums that show up as there but will not play

I uploaded several (20 or 30) music albums to my Itunes library between 2019 and 2023. I could access those albums from my TV (with itunes) and from my iPhone with no problems. I think it has been since last year that I last accessed them, but I wanted to play my Christmas albums yesterday. I find that I am unable to play several of them. They show up in the library and I can click on play. But it just sits there.

I downloaded the albums (they were .m4a files. I converted them to .wav files and can play them locally on my computer.

How do I replace the existing files on iTunes with the ones I've downloaded and reconverted.

I actually don't care how to do it, I just want to be able to play my albums again. Any ideas out there?