Hi @johnjohn123 ,
I think your needs can be met. Based on the idea of @Anonymous , I want to add something.
The point is to judge the value of the column when submitting.
If the value is "Submitted", modify the DefaultMode property, otherwise do not modify.
I assume:
"Approval Status" is a choice column. It has two options, one is "Submitted" and the other is "Unsubmitted".
I did a test for you:
1\ This is my test list 'LIST 58'

2\ Add an edit form 'EditForm1' and set its DefaultMode property to:
Thevar // This is a variable name, it will be created later
3\ Add a button control and set its onselect property to:
SubmitForm(EditForm1);If(EditForm1.LastSubmit.'Approval Status'.Value="Submitted",Set(Thevar,FormMode.View),Set(Thevar,FormMode.Edit))
4\ The result is as follows:

Best Regards,
Wearsky
If my post helps, then please consider Accept it as the solution to help others. Thanks.