The rules stated clearly that it is not allowed to edit graphics to use as title screen? Custom edit title screen will have huge benefit because it is more appealing.

Are they using edited images as their cover photo for Itch or in their actual game?
In RPG Maker MV and MZ (Not sure if it was possible in VX or ACE.) you can have it draw the name of your game on the title screen.

Are you talking about the title screen in game or the cover to the itch.io page?  I made one for the itch page but  for my game is the default one.  The rules say nothing against this.

Most of the entries have custom Cover (for the itch.io page), but actual game uses RTP images.. Should check the actual game itself.

I used it in the cover image of the submission. The game uses RTP assets only. Check the games before pointing the finger at other contestants, please.