Hate to be the bearer of bad news but companies like Google don't care about where you're based out of and will sponsor your visa if they think you'd be a valuable addition. If anything, getting a TN visa is the easiest type of visa for employers. I'm working at FAANG and recently got rejected to the three Google positions I applied for. Later, a Google recruiter reached out to me personally on my email to find a role that would better fit. Currently, this market is tough with the number of layoffs, and Google has to deal with thousands of applicants for each role. I'd assume your resume got screened out. I wouldn't get disheartened. Keep on applying and improve your resume and experience!

I also want to mention that I'm also Canadian and found it hard to initially break through into US based jobs. It was hard work and building up my resume that helped me get my first US based job and then i jumped around and continued to improve until I got to FAANG. I'm a senior now and even I'm currently getting rejected from job postings at companies I wouldn't ever want to join (interview practice lol) because of the market conditions. As a senior SWE, I'm also finding it harder than my usual job searches and there's only really Senior postings i'm seeing. Entry level roles are probably being bombarded with folks that are willing to take down levels too just for the sake of a job. Also I want to mention that I've never mentioned that I'm a Canadian citizen or require a Visa in my resume. They won't ask you about visa requirements until the initial screen with HR. Even start ups don't have difficulty getting TN visas for Canadians. Also i've never written a cover letter and companies that ask for one aren't working for. Your resume should speak for itself. Good luck