[solardev]

If you want to use LEMP, I'd look into at least abstracting the lower parts of the stack (mainly the L and E, maybe the M too) into vendor-supported services. You can use Google App Engine to host the PHP code on managed auto-scaling infra, DigitalOcean or another hosted MySQL, or virtualize the whole thing using something like Cloudways.

The more you can offload to managed services, the more time you can spend coding application logic (the P part) instead of managing OS and SQL servers updates, Nginx rules, etc. A lot of that is commoditized these days and managed by specialized companies & people & scripts who can do it cheaper, faster, and better than you (if you don't have much experience).

There are legit use cases for rolling your own infra (or rolling your own everything), but "I'm a new solo web dev needing to launch a startup web app" probably isn't one of them. Any one part of that stack (LEMP) can require a lot of knowledge and setup and regular maintenance, and doing those things without downtime can be difficult, especially without a mentor/partner to help you. If you're a one-dev shop / tiny startup, let the specialized vendors take some load off while you grow. You can always in-house the stack later, once you can afford more experienced people (or you yourself get more experience).