How to get the first 10 customers for my SaaS? (I will not promote)

Hi everyone,Last week, I launched my first SaaS product and successfully acquired my first customer by sending emails to people on my waiting list. During an interview, he mentioned that he found my landing page while searching for a job in Europe. My product in one sentence: A platform that helps South American tech professionals find better job opportunities in European tech companies that offer quicker visa processing by automatically generating resumes and cover letters, and assisting them in tracking their applications. It's a subscription-based service, billed every two weeks. My main target audience: Males aged 19-40 who are either looking for internships or are dissatisfied with the political situation and want to change jobs. What I'm doing so far: I've been sending cold emails to professors at tech universities in South America, asking for a call to discuss sharing my platform with their students. I started this a few days ago, and while the emails have been opened, I haven't received any responses. I understand that there could be several factors affecting this, such as the copy of my email, the lack of free trials, or the reluctance of teachers to promote something that requires payment from students. My question is: If the cold emails aren't working, what should I do next? Should I consider reaching out on LinkedIn, or perhaps invest in Google Ads (which previously helped me gather sign-ups for the waiting list)? Any advice would be greatly appreciated!