Correct me if I am wrong, but I think you are talking about the RSC Journal Physical Chemistry Chemical Physics (PCCP - https://www.rsc.org/journals-books-databases/about-journals/pccp/).
Like you can see, there are articles that you have to pay to access (https://pubs.rsc.org/en/content/articlelanding/2022/cp/d2cp01555b), and some you do not have to pay, only have an account (Article Insights into 2D materials
)
This gives us the hint that the Journal can accept both open access and subscription (free of charge publication) papers.
I am sorry, I didn't understand your question correctly. If it is, the answer to your question about open acces is precisely in the guidelines of the journal:
"How to publish open access
Enhance the visibility of your research, and meet your funder and institutional requirements"