According to this link https://community.atlassian.com/t5/Confluence-questions/Edit-permissions-on-only-one-page-how-to-set-up/qaq-p/731478 there is isn't an effective way to solve this problem.
The way you can do this is to let a user have edit permission and instead restrict the other pages.
To restrict a page you need to be in the page you want and then click in the top right corner with three dots.
But as the link suggest, it is not really recommended to set it up that way.
Hope that help with your issue!
Here’s another edition of “What’s New” this month in Confluence Cloud. Quickly (and more easily) adjust permission settings We know that sometimes the layers of space permissions and page restric...
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