which runs slow in every first day of the Transaction.
SSRS is mainly a web server and it's by design that a web server goes into sleep after a period of idle. The first access to SSRS starts it up and that can take some time.
My Question here is restarting SSRS from PowerShell on a Daily basis is good Choice
No, it won't change the behaviour, the first report call takes some time.
And taht the soultion, the "first call", so use PowerShell for a first report request instead, it's a simple Html client request.