Hi @Anonymous ,
Do you mean that you could not use sharepoint custom form to update your list?
Firstly, I agree with @WarrenBelz . Try to remove the "required" settings.
Secondly, could you change your form to standard form and try to update?
I would like to know whether you have problems in your sharepoint list.
list settings->Form settings

Thirdly, did you make any customizations on your sharepoint custom form?
If you change any controls or settings on the default generated custom form, maybe you need to change the formulas about updating.
I need to know the changed fields' settings: control settings, datacards' Update.
Also, please check your SharePointForm1's OnEdit, OnSave, OnView properties.

Do not forget to save and publish your app when you finish editing this custom form.
Best regards,