If you haven’t already heard, SQL 2022 has introduced a new built-in system function called GREATEST. Simply put, it is to a set of columns, variables, expressions etc. what the MAX function is to a set of values (i.e., rows) of a single column or expression. The opposite of GREATEST function is LEAST function which returns the smallest value from the supplied list of columns, variables, constants etc. GREATEST & LEAST can be considered a pair, just as MIN/MAX functions are.
So, on a SQL Server 2022 instance, you can simply call GREATEST function with list of columns, variables, or