It's not the same company as day one... Now is owned by Oppo. So basically is a Oppo phone that is for sure.
And if you are looking for those super open phones to unlock add customs roms... Look another way.
For other stuff... Idk I have one it works well for me and it was a much cheaper alternative to Samsung or iPhone and with latest Snapdragon and plenty of ram and good hardware. Cameras idk if others are better I barely take pictures and usually I don't care a lot for the quality.
And the Chinese fast charging thing they have is amazing. (Also supports USB c pd quick charging although much slower)
Now only included on Apple One.