Easily convert UNIX timestamp to datetime in SQL Server

Simple copy-and-paste example:

DECLARE @timestamp BIGINT = 1661881445;
SELECT DATEADD(S, @timestamp, '1970-01-01')

Or for values greater than 2147483647

DECLARE @t AS BIGINT = 4956739375
DECLARE @oneyear AS INT = 31622400
SELECT DATEADD(SECOND, @t % @oneyear, DATEADD(YEAR, @t / @oneyear, '1970-01-01'))