I mean you could pick one of these and try to get in. If it's about SW dev, it would probably make things easier if it's backend related or at least including backend like fullstack. Actually backend stacks are also evolving quite slowly. What usually impresses people is something that you built with technology that you really like. E.g. once at an interview there was someone presenting I think a web based managing tool for music albums. Like end-to-end working, not many feature but just worked. This kind of software exists hundreds of times, it's not about the idea but the execution. Or like one time I applied for a job and showed them my self-hosting stack (Email, Web server, Wiki) written entirely in Ansible. You could pick a stack that is both in demand and that you like, pick a possible idea and realize it. I guess learning by doing is anyway easier. You could then host it on Azure or Heroku for free. (Or EC2 or EKS if you want to include DevOps) Also basic design can be realized with Bootstrap or whatever is the current go-to-framework for that. And then perhaps put it on Github in a single commit once you're done. Most devs don't involve in Opensource activity and get fine very well anyways. FWIW I appreciate working with fullstack+devops because of the changing tasks but don't expect any badges because of the broader knowledge which is then not necessarily very deep. Also it's just work after all :-) But I admit it's easier to find new jobs.
So yeah, learning by doing and there are blogs posts/Stackoverflow/YouTube videos/forums/Discord chats for everything if you're stuck.