What's the best and easy way to build a cloud based SaaS product?

am working on a project and don't have experience with developing applications, I want like the BEST and EASY way to build cloud based SaaS product.

Can anyone tell which tech stack I should use, which backend lang/framework, db, which cloud company etc? I know only php in backend as of now but am thinking to first learn js and then nodeJS and then use it for backend and for db am thinking to use mysql.

There's something which might affect your answer, am actually not expecting much traffic on it not even in future. Please tell considering both the scenarios, application with very low traffic expectation and application with high traffic.