Hi @Anonymous ,
Could you please tell me where your data is stored? What are the data types of the two columns?
I have made a simple test for your reference.
1.Here is my SharePoint list.

2. Here is my App.
If(IsEmpty(Filter(FiscalList,'Fiscal year'=DataCardValue5.Text)),1,
Sum(First(Sort(Filter(FiscalList,'Fiscal year'=DataCardValue5.Text),Event,Descending)).Event,1))
Text(Now(),"yyyy")

Result Screenshots:


Best Regards,
Charlie Choi