Need feedback please alternative to Vanta/Conveyor because I hate subscriptions

I run a small B2B SaaS (Ok, not really it’s my mom’s business but she considers me a partner in it). We just spent 3 weeks chasing a $$k enterprise deal.
At the finish line, they sent a 250-row Excel security questionnaire. It took me my entire weekend to fill out.
I looked at competitors ($5k+/year, overkill for us). Just wanted something simple: drag file, pay once, done.
Thinking about building a dead-simple utility:
Upload blank questionnaire
Upload your security docs
AI fills it out
Download completed filePay once (~$99), no subscription
No sales calls. Data gets deleted 24Hrs after you pay. No Onboarding Bullshyt.
Question for founders: Is this actually a problem worth solving? Or have you found better ways to handle these?
Also: What would make you trust AI-generated security answers enough to submit them to a buyer?
(Not trying to sell anything – genuinely trying to validate if this is a real pain point or just me complaining)