Well theoretically you can expand your structure with more columns (let’s say purchase 1 name, purchase 1 timestamp, purchase 2 name, etc. all the way to purchase 5). Not the cleanest structure in my opinion, but if row count is a problem for you then ok.
Then in Integromat/Make, do a search row step and then a router.
If purchase 1 name is empty then add an update row step to write to purchase 1 name and purchase 1 timestamp.
If purchase 1 name is not empty and purchase 2 name is empty then write to purchase 2 name and purchase 2 timestamp.
If purchase 2 name is not empty and purchase 3 name is empty then write to purchase 3 name and purchase 3 timestamp.
All the way to purchase 5.
For displaying it in an inline list, please adapt this method.