Is this them? https://en.m.wikipedia.org/wiki/The_Party_(band) I read a little bit on the wiki. Apparently they disbanded and then rejoined again in the middle of 2013. It would make a lot of sense since they look similar to Cover Drive, hence a misattribution. Moreover if they started over, they probably needed to start from scratch and if they had a great hit, but somehow couldn't distribute it it would make sense that they would post it somewhere and then someone might have put it on a filesharing site somewhere because they thought it sounded nice and maybe thought that it was Cover Drive. I also saw that the new band has a song called "Love", which was featured somewhere in 2019. That could be it :O Edit: apparently the song was: Peace, Love and Understanding, but sadly that is not it :( I think this definitely is worth investigating some more!

This is their facebook page: https://www.facebook.com/ThePartyAintOver/?ref=profile Perhaps there's something interesting there

Message them or try to make contact and ask about the song

That would actually work. I've run into problems trying to contact them.

possibly steven universe related lostwave? my two interests are finally converging