You're kind of contradicting yourself:
"Fallen is one of my fav albums ever, wanted to re-listen it but can't sadly. As I understand all pre-Fallen songs was deleted for some reason."
So you want to listen to Fallen again, but you're upset because pre-*Fallen, as in songs *before Fallen, are not on Spotify. So which ones do you want to listen to? Fallen or before Fallen?
And you can always buy the CD or download the mp3s if you want to listen to the album
See if you can find the 1080p MPEG2 rip of My Immortal that came from MHD back in the day. I lost my copy some years back and haven't been able to find it since.
Once you have that highest-quality source, use FFMpeg to split it into images (should be somewhere between 5000 and 8000 images), then you can throw each image at a cloud AI colorization engine. This one is cheap enough that you'd pay ~10 bucks in per-image fees, then fractions of a penny per image in CPU time. I guess it'd be around $40.
Reassemble the images into a video with FFMpeg and then mix the audio back in—colorized version ready to go.
It might look funny though. Depends on how good the AI algorithm is.
I think she uses this microphone. I added it to my Amazon wishlist to save it when I saw her mention it in a video she shared (never going to buy it) Link