I would assume Sony keeps the rights to content created in Dreams. Whether that would extend to you OC, you would have to read the license agreements.
I found this though.
https://www.playstation.com/en-us/legal/dreams-creators-beta-agreement/> 4. User Generated Content.
You may have the option to create content such as pictures, photographs, renderings, videos, animation, sounds, music, game play, game related materials, or other information (“User Material”) through the Beta Product. To the extent permitted by law, you license SIE a royalty-free and perpetual right to use, distribute, copy, modify, display, and publish your User Material for any reason without any restrictions or payments to you or any third parties. You acknowledge that you have received good and valuable consideration from SIE for the license of the rights in your User Material. SIE may sublicense its rights to your User Material to any third party, including its affiliates. You hereby waive, to the extent permitted by law, all claims, including any moral or patrimonial rights, against SIE and its affiliates or any third party’s use of the User Material. By creating, posting, streaming, transmitting or providing SIE any User Material, you represent and warrant that your User Material does not infringe on the intellectual property or other rights of any third party and is not obscene, defamatory, offensive or an advertisement or solicitation of business and you have the appropriate rights to use, create, post, distribute, transmit and provide User Material and to grant SIE the foregoing license. You must cooperate with SIE in resolving any dispute that may arise from your User Material.