I was told that this gets bad when it arrives at DC, is that true?

Yes, although it is rare and progress is quite slow. (I read up to chapter 229.)

Has this been abandoned?

Try reading the synopsis. There are the answers you are looking for. That MC is NOT Peter from the comics, and never was. Your way of acting or personality does not need to be the same as in the comics or films because it is not the same character.

The MC will change his height and hair with the help of the system.

harem?

They say it's at the end of chapter 189.