How to approach a multitenant architecture solution?

Basically all the issues that you commented here is the reason I am keep in the infinite loop about this.

I know how painful and unmanageable a non-multi-tenant platform could become but I think that the source code could become more tedious to work with.

What does AWS does? Or something like https://www.onelogin.com/ and Identity Security for the Digital Enterprise | Ping Identity

What would be your speculations about these systems?

Btw, I am trying to create these SaaS as OTP applications that you would normally use and plug into your system so code readability and simplicity matters for me, but, I wouldn’t trade off to do the right thing.