Jep, I also thought that it would be the first single of their new album. Since so much time has passed and especially since TDTYF is not part of their current live setlist, I'm sure we won't find it on the new album, it will remain a standalone release, just like C-H-E-M-I-C-A-L.
FY was released about half a year before NG and that was (I think) the longest time span between first official single and album release. If TDTYF is indeed on Chem10, which I expect in late 2022 at the earliest, this timespan would be nearly three times as long.
I'm totally fine with a standalone release. Ages ago we got to hear a lot of the tracks that didn't make it for whatever reasons onto the albums as B-Sides, since we pretty much don't get single releases anymore why not some short EPs instead?