Two part answer 1/ how do I built it 2/ how do I run it.
The run part became easy the last few years:
Dockerize all the things, run them on AWS ECS with Fargate (and add whatever else you might need, e.g. ELB, S3, SQS, ...), no servers to setup or maintain.
The built part, that actually became harder... You need to figure out the best tools for whatever problem you're trying to solve, and the list of tools keeps growing. I default to very conservative standards, because I'm familiar and productive with them: Java (Spring Boot), Vue.js and PostGRES, with sometimes a bit of Node or Python and some ElasticSearch or DynamoDB thrown in the mix.
The run part became easy the last few years: Dockerize all the things, run them on AWS ECS with Fargate (and add whatever else you might need, e.g. ELB, S3, SQS, ...), no servers to setup or maintain.
The built part, that actually became harder... You need to figure out the best tools for whatever problem you're trying to solve, and the list of tools keeps growing. I default to very conservative standards, because I'm familiar and productive with them: Java (Spring Boot), Vue.js and PostGRES, with sometimes a bit of Node or Python and some ElasticSearch or DynamoDB thrown in the mix.