How to find working distribution channels for my SaaS

Hey people! I am building a SaaS in the automated QA testing sphere(visual regression testing). I am currently struggling with finding sustainable channels to get some eyes on our product though.

Things that worked in the past: - hackernews frontpage - tldr; newsletter - top of subreddits - viral twitter posts

But all of these are not super sustainable as they spike and flatline(I doubt you can also reuse them frequently). I am currently focusing on content marketing and SEO, but not sure it's the right channel to get the leads who will convert.

Looking for ideas and also very happy to chat and explore the options trough conversation! thanks!