I'm the creator of https://www.saaspegasus.com/ and would love to have you as a customer, and very happy to answer any questions you have about the Pegasus product, community, etc.

That said, all of the popular boilerplates have been created by individuals or teams who are passionate about their frameworks (in my case Django) and have significant experience building products on top of them (in my case 10+ years). All of them will drastically reduce your time to MVP and likely be a better foundation than you'd author on your own.

I actually would choose a language/framework first and then choose a boilerplate based on that. The boilerplate will get you far, but ultimately you're still going to be doing lots more dev in the framework, so you should pick one you like. Django and Rails and to some extent Laravel are comparable - mature frameworks with lots of batteries included, mostly server-render HTML by default. JavaScript is its own separate beast with a more fractured ecosystem, but tighter integration with the front end. I'm obviously biased towards Python because it's a wonderful language to work with and has a great community and third-party package ecosystem. But honestly, any of these are great choices and will help you launch your first product way faster.

There's a huge list of SaaS boilerplates broken down by language available here: https://github.com/smirnov-am/awesome-saas-boilerplates

Good luck!