First of all the default data store is completely fine. Data will not fail and wipe any players’ data. My friend and I have once made a game that peaked at 3k players. All the data was completely fine. DataStoreService is fine but requires skill to make correctly and to a custom module. Profile Service just coded it correctly and made it a module which was easy to use.
Ignoring the fact that you completely misunderstood how the default data store works… The reason youtubers put the functions and everything else in a module script is so they can use it in other scripts. A module script is MUCH better than putting it in a regular script.
Regarding your tutorial, you have copied the ENTIRE example code that Profile Service has. You didn’t even replace a word. This would be fine if you explained the example code in depth. But you only wrote what to do.
Make a new server script, and paste this code into it:
??? You calling this a tutorial ???
Where to learn from
For everyone seeing this post I recommend learning from youtubers or from the profile service page.
Never copy scripts that you don’t know how work and actually make and learn how to make them yourself.