Do not restrict yourself to a particular domain; you should know a bit of everything - be it backend, frontend, infra, or design.
This way, you avoid being dependent on others for launching your side hustles and makes you invincible.
The only reason I can pull off so many side hustles is that I can do a bit of everything; here’s the tech I know in-depth.
Backend: Golang, Python, NodeJS Frontend: NuxtJS (VueJS) Design: Bulma CSS Infra: AWS
If there was one piece of advice that you should take from me, it must be this.
Happy Learning.