Now I'm at another SaaS company that builds a CRM. Definitely less interesting on a purely subject/industry level but I'm happily learning new things that are personally interesting/satisfying - finally a chance to work with React, ES6, DevOps, even ML stuff. And just started a book club as well, going over structure and interpretation of computer programs.
Plus I gave myself a 50% raise and better benefits all around at this company - win win win. Granted I was obviously underpaid at my last job.
Don't stay if you're unhappy - there are plenty of places to work at that should keep you technically interested as a software engineer these days.