Spent 8 months developing job automation tool with 40 signups but no active users. How to validate quickly?

Hello,

I have spent almost 8 months developing a tool to make it easier for people to land a job. Initially it started as a job board with the premise of using AI to tailor-match jobs to an applicant based on their experiences and skills. The user would upload a CV and based on that a model would be used to score jobs and return matches.

I got about 40 people sign up on a waiting list. I used a combination of LinkedIn, YouTube and my personal blog to make the announcement and get reach. This version of the app took about 5 months to develop. At this point, I looked at some competitors and realised I wasn't offering enough value to be able to make it a paid product. Btw, the app had first time users at this point (33 in total) but no active.

So, I decided to pivot and make a chrome extension that would integrate with the app and auto apply to jobs on behalf of the user. Fast forward 3 more months and I have a basic version of the extension published in the store with a free trial and a paid plan.

I tried as best I could to validate before building and I realise as I am writing this I might have failed at that. At this point, I really need some validation.

I feel overwhelmed with how to market the product and validate it? What is the quickest way to validate so I don't spend another 6 months building features no one will use. I have sent an email out to 40 people on my mailing list but resulted in no conversion (no chrome extension download).
My plan is to make a LinkedIn post (I've had good reach on LI in the past ) with a link to the demo. What then? SEO, paid ads, cold outreach? The extension is in a useable state but needs polish but I refuse to spend more time developing it before getting some actual users.

Here's the landing page: https://jobsweeperai.com, app is live here https://app.jobsweeperai.com. The landing page needs to be updated with the new update. There is a demo here showing the auto fill in action: https://youtu.be/uXHiRFrEQfM

Would love some advice on how to proceed!