What tech stack to use?

I need to create an application that is essentially a CRUD one ; it will become a SaaS once it's done enough.

What tech stack to use?

I need to do a "working wireframe" (=> everything but not nice design, logo, colors) within ten days (during evenings and week-ends). I will then show it to potential (?) customers.

It needs to work great on laptop, on mobile devices, and should be able to work in the future with voice commands. In any case, it has to be really quick/reactive, super simple+beautiful=pure.

My tech experience is PHP (with frameworks), bootstrap, jQuery, and a small slice of Angular (so pretty "old"-fashioned tech stack).

A technology with a pretty looong learning curve wouldn't be that interesting because I wouldn't be able to do a prototype within days, and I may get discouraged quickly.

What would be the best choice, and why?