Need tips for my project

Hi guys. This is my first post but I'm active reading you all the time.

My gf is a mental health nurse and she spent around one hour to write a doctor referral letter after a patient assessment. I saw that the process is quite easy to do with a form and I started working on a little app able to do it. After I asked her what about your colleges and she said everybody hate writing GP letters and everybody take so long.

I started dropping surveys in FB groups for mental health workers and I got 61 people opinion. 60% of the people spent Up to one hour doing this letters and around 42% of the 61 were willing to pay a netflix-like amount to do letters in 5 minutes.

This is a very specific niche that probably need some approval from NHS and be sure they can use it as nurse.

I have a landing page on squarespace service http://getcarta.app and working full-time on the app at home. I'm also running a 2£/day FB campaign since three weeks ago targeting mental health nurses and other profiles that do letters and I only got 4 registered to the newsletter waiting list. Actually last week o wrote them a message to ask if they will like to have early access for free and try the app when it's released but noone replied back. Lol.

This is a very specific niche and I realised that only a little % of them (around 20%) were spending 15min do to the letters because the clinic have a software to do it. But the others doesn't. My tool will do a specific thing not like those enterprise clinic softwares and I guessed that the customer will be the mental health worker and not the clinic. My customers don't know that they need it. And probably that's my main target. I could not find any other company doing it. (Probably some enterprise expensive software for clinics)

I'm looking for tips and your help to guide me on any thing that it could help me.

Thanks!