Collected merge statement alternatives as their use can consolidate the insert/update sql code necessary but come with known risks

The Case of the Blocking Merge Statement (LCK_M_RS_U locks)
Use Caution with SQL Server’s MERGE Statement
SQL Server 2008 introduced the MERGE statement, which promised to be a simpler way to combine insert/update/delete statements, such as those used during ETL (extract, transform and load) operations. However, MERGE originally shipped with several wrong re
MERGE (Transact-SQL) - SQL Server
MERGE (Transact-SQL)

And throwing in a NOLOCK use with caution only

Serializable Lock Hints Detected - Brent Ozar Unlimited®
Serializable Lock Hints Detected If a query uses the SERIALIZABLE isolation level or HOLDLOCK hints, SQL Server will hold shared range locks until a transaction is completed. Normally SQL Server lets go of locks as soon as it’s done processing that part of a query, but here, the query has forced all…