Insert blocking update query on table in SQL Server - sql

Question

I have a table "Alert_List" with two sessions are running on it.
Session 1:
insert into Alert_List values ( "required values")
Session 2:
Update A
set Active = 0
from Alert_List A
left join STG_Alert B on A.Alert_List_Id = B.Alert_List_Id
left join STG_UserID C on A.UserID = C.UserID
where B.Alert_List_Id is null and C.UserID is null
Here STG_Alert,STG_UserIDare staging tables which will have a few selected Alert_List_Id and UserID which are not required to be deactivated.
Indexes on Alert_List as below.
ALTER TABLE [dbo].[Alert_List] ADD CONSTRAINT [PK_EA_List] PRIMARY KEY CLUSTERED
(
[Alert_List_Id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON)
GO
CREATE NONCLUSTERED INDEX [Alert_List_INDEX] ON [dbo].[Alert_List]
(
[AVE_Id] ASC,
[Request_Id] ASC,
[User_Id] ASC,
Active ASC,
[Process_Id] ASC,
[Status_Id] ASC
)
INCLUDE ( [Alert_List_Id]) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON)
GO
CREATE NONCLUSTERED INDEX [indexeaml] ON [dbo].[Alert_List]
(
[User_Id] ASC,
[Process_Id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON)
GO
One query from above two failing with below error.
Transaction (Process ID 85) was deadlocked on lock resources with another process and has been chosen as the deadlock victim. Rerun the transaction.
I dont want to use WITH(NOLOCK) nor ALLOW_SNAPSHOT_ISOLATION in this case.
Let me know if you have any other ways to solve this issue.