Appending columns

I have a set of data that looks like this example (although th real one has >600 "log work" columns, each of which has a name, date and time which I intend to extract after I figure this part out)

I need to be able to compare each "log work" entry with others from the same assignee, and my thoughts were to append the columns onto each other in a new table somehow like so (this is just imported from a manually created excel sheet):

I managed to get several of the columns appended to each other in a new table using DAX but that required manually typing out each column name, and in the real data set I have over 600 (which could change to be more or less depending on the database users) so I'm not really sure if typing out a few thousand lines of code just to create a table that just won't take in data from the database after a certain number of columns is worth it. If anyone has an idea of how I could go about either looping my dax code through multiple columns based on their names, or if anyone just has an alternative way of comparing the things I need to that would be really helpful.