Bootstrap Studio Smart Form is awesome. It is simple and it works.
But if you need something extra, I just launched a SaaS for forms backend. Just create your form any way you like, and get a URL for your form action from Firaform.com and use that. Firaform will store the data for you. It supports file upload, CAPTCHA, email notification, optional field validation, etc… just check it out.
There is a free account that allows up to 250 submissions per month.
Let me know if you think. And I here if you have questions.