To upgrade from Reporting Services 2016 and earlier to Reporting Services 2017 and later, you need to migrate your Reporting Services installation. You can refer to this document: https://learn.microsoft.com/en-us/sql/reporting-services/install-windows/migrate-a-reporting-services-installation-native-mode?view=sql-server-ver16.
I also found this link: https://www.sqlservercentral.com/articles/migrating-sql-server-reporting-services, maybe you can use it as a reference.
Best regards,
Aniya