In order to get Sunbeam effect for idle, executions, free roam and combat you would need to do the following...
1. Be apart of the Ubisoft Club - Idle effect
2. Buy the deluxe, gold or collector edition, cheapest one is 65$ retail - Execution effect
3. Buy the year 1 hero bundle which is 30$ - Combat and free roam effect
Which, after nearly 100$ retail price, you will have all the sunbeam effects. Unless for some reason, you happen to play Black Prior who can use all of them for 5,000 in game currency each.
You can buy a used copy mind you for around 25$, but it still comes out to around 50$ to obtain all the effects.
This effect cost nearly if not more to obtain than the base game at release! Please either make changes to the rewards you get for the hero bundle and the bonus editions or just make them purchaseable for a lot of ingame currency.