The second one sort of depends on the player. I've had a few players that have made absolutely ridiculous characters but played them very well and it was a good experience.
The first one is a strong no. I've never seen anyone who does a broken meta build do anything beyond ruin everyone's time and complain (or quit) if the DM reins them in at all.
Maybe I need another coffee but I'm a little confused.
So this site (named after a previous writing practice workshop that shut down after a series of scandals) is trying to do the same thing but isn't actually hosting anything and is more or less pointing to a Reddit megathread with like over a dozen other writing practice workshops?
Edit: Is the point of this just to practice writing a novel for self achievement?