We use Go for the first-off due to our knowledge of it. Second off, it's highly performant and optimized for scalability. We run it using dockerized containers for our backend REST APIs.
For Frontend, we use React with Next.js at vercel. We use NextJS here mostly due to our need for Server Side Rendering and easier route management.
For Database, we use MySQL as it is first-off free and always has been in use with us. We use Google Cloud SQL from GCP that manages its storage and versions along with HA.
All stacks are free to use and get the best juice out of the system. We also use Redis for caching for enterprise-grade apps where data retrieval latency matters the most.
I am a business analyst with many years of experience. Your stack looks good to me. Go is a great choice for backend speed, React is the most used JS front-end library/framework, and Next will help the SEO of your web apps, due to its feature to be as a Server-Side Rendering framework developed on top of React. My only advice is to start looking at Postgres as a relational database instead of MySQL. Postgres is 100% open source. MySQL is owned by Oracle, and the only way to go totally free is having the community edition which is limited. MySQL is a simpler database. Postgres can handle massive databases, it is an Object-Relational with extensive features. Postgres has native NoSQL capabilities to deal with complex queries. There is PGAdmin UI to handle Postgres databases design, similar as Workbench is for mySQL.