Next.js, SSR, GraphQL clients, WASM based apps, React server components, monorepos, micro-frontends etc. are all pretty hot right now.
Start with learning JS and React in depth (Akshay Saini's series, Kyle Simpson's books).
Make some interesting React projects with some of the above mentioned hot tech - preferably Next.js
Learn about frontend architecture and system design - state design and management, modularised component design with dependency injection, CDN abstractions, caching patterns, bundle-size optimisations, SEO optimisations etc.
Then apply some of the learnings from all of the above system design topics to your previous project. You will gain enough knowledge and expertise to be at the top of the market.