Nice rundown of your thoughts when trying to assemble a tech stack. I can totally relate to the whirlwind of choices out there and trying to match them up to what would work and what you'd possibly enjoy using. But that doesn't mean you HAVE TO use new tech.
Yes, new tech has benefits... and drawbacks. Probably in the same ratio as older tech after years of working hands on with the stack and trying to bend it to your will. I'm not bashing the new stuff at all, but never feel like what you have experience in is less than worthy, in this case PHP. If you really enjoyed PHP, pick it back up and start using it again.
Most of the exotic and extreme efficiency come from heavy customization and creative abstractions. So when you step back and think about it, these "faster" race wars can be insightful, but also may serve to be amusing at best in the long run.
Would love to hear more as you dive into the development and hit milestones and revelations along the way. Hope you enjoy the app build!
RE: The challenge of starting a new development project