SSRS subscriptions after failover
I managed this situation severals times.
The best thing is to not modify the subscrition jobs created by SSRS service. After all they do not have a job schedule. The schedules are managed internally in the SSRS database.
With SQL Server Always on AG the jobs are not replicated because their definition is inside the msdb.
So in an Alwayson AG setup for SSRS, you have an SSRS database inside an AG but you have two (or more) msdb that can contain ssrs jobs and two (or more) SSRS services.
Each of the runnig SSRS services will execute the scheduled jobs handling dividing the workload trough the ssrs database. Here I'm supposing you configured the SSRS to use the AG listener for db connection.
Remember to place the proper ssrs service user in msdb database role (RSExecRole) of each instances as described here:
https://docs.microsoft.com/it-it/sql/reporting-services/security/create-the-rsexecrole?view=sql-server-ver15
The SSRS subscription jobs are recreated every time ssrs starts so when a failover occurs you have to start or restart ssrs service to handle this.
Then what happend depends on what is the role of AG you designed: HA or DR.
In the DR design I suggest you to not leave SSRS service turned off because it will execute subscription on a DR site and this usualy is not good.
In an HA design you could leave the SSRS service turned on so you balance the workload between the two instances (keep attention to licensing too)