Why not give it a go with a band you know personally? Or try to start one.

Regardless of whether the lyrics are good, it complicates things in terms of songwriting credit and what not. It might even go against their contract. Usually a band is established because they have a good lyricist(s) within the band or they made it without good lyrics. Just saying this to be realistic, you'd be cutting another small piece of the royalty pie from the band. That's a tough sell, especially in a genre like metal where a lot of band don't make a ton of money as it is. It can also come off as insulting. I know you don't intend it that way but... well, how would you feel if someone asked you to read their poetry instead of your own?

If a band does bring in another writer it isn't random. It's usually someone as established as them or more.