Ideas for an editable, secure Awards Entry Form

My client needs an awards entry form on their website and there's lots of options (SQSP internal, JotForm, Snapforms, etc.). The form is long and it's like the person filling it in will need more than one sitting, so there needs to be a login and save capability. There is no payment required, just the form. Ideas and input gratefully received. Thanks SQSP community.

Google Forms has a Allow response editing setting that may help with this.

I would test that feature out to see how flexible it is. Like start a session and not finish. Wait a day. Edit some more but don't finish. Come back and go back to previous sections. See how it works from the form filers view and the form manager's view.