The lonely is a dsbm band from mexico, i searched it on the metallum and didnt appear so i tried adding it and said that its blacklisted. why?

Blacklisted based on this split. The first track is not metal, while the other one is. So we are gonna wait for a more substantial release.

so what is it? rock? indie? the split says ''post-black metal''

There are actually three full-length albums on the band's official YouTube channel:

Decayed: https://www.youtube.com/watch?v=gtPeWWgJK0s
Abomination: https://www.youtube.com/watch?v=UD4Viey9EPY
Inhuman: https://www.youtube.com/watch?v=2HmZAZX1iBg

The artist officially split up 5 days ago at the time of this reply and stated in this Instagram post that all of his songs would be uploaded to other platforms in the coming weeks. I assume we should wait until then for a reconsideration?

Correct.

Not really grounds for a proper re-evaluation, but it looks like this project has a Spotify now. Not sure if it actually belongs to the artist or if the page is a result of the artist being listed on collaborative releases.

https://open.spotify.com/artist/3M1CH6NPxo4rMpuJnVEb3T

Felt this was significant enough to put here regardless. I'll check back when the artist's three actual albums are added.