Hi, I have noticed that on many of the setup steps, once you save, you cannot delete that data

If you're on a project, and accidently save something that is incorrect, how would you correct this? Would DBA's delete it? Or is it commmon place just to create a new record, and change the incorrect record to "Do Not Use" or something like that?

Many Thanks

No do we not ask DBAs to delete it through the back end. That voids support.
Disable the record where ever you can.
Otherwise simply add "Do not use" in front of it.
It does happen once in a while. For examples you have to be very careful when creating ledgers in production. Always verify each field three times by matching it to test environment.
Mistakes do happen. Other examples are categories and consolidation definitions where you have to add "Do not use" in front of it.