https://medium.com/h-lab/how-to-deploy-vue-with-nginx-on-sub-path-ed8eadbc1bc5

vue.config.js

module.exports = {
  publicPath: process.env.APP_BASE_PATH
}

Vuej3

https://stackoverflow.com/questions/43879418/deploy-vuejs-app-in-a-subdirectory

module.exports = {
  baseUrl: "./"
};