Is there a way to create a pop up that would warn the user that they are about to modify a field? I want them to be able to make changes but I’ve run into a number of issues with people unintentionally changing data.

Is this a privilege set issue or is there a scripting route I can take? or???

I think a warning is a bad choice. That's going to get annoying to users real fast.

You could "lock" a record by default and require users to click a button to unlock it and edit it.

Thanks for the suggestion. Would you suggest I create a duplicate layout where the fields can be entered, then use a button to go to that layout? I’m not sure how to get back to the locked layout if they scroll to the next record.

Use the record level access privileges to lock the record. I've done it this way:

1) make a global field in the table - call it "recid_g"

2) make sure each record has a unique id (they should anyway) call it "recid"

Create a privilege set with the calculation to allow editing records, the calculation is

recid = recid_g

To unlock a record, create a script that puts the record's id into the global field. To lock it again, clear the global field.