There is often no clear progression after those first steps, and it’s easy to get discouraged and fall off. A lot of the material you’ll find is focused on the somewhat experienced developer learning a new framework and not on learning what’s required to become an expert. There is a gap at this point that you need to fill yourself so you have new material to learn when you’re ready to continue.
You have to trust that you can build your own path at this point. Nobody can tell you everything you must learn, because you need to learn from your own experiences. At this point, you’ll deliberately seek out information that may not be directly related to the subject, but that you can integrate with what you already know.
You also have to challenge yourself and deliberately focus on learning hard things and growing if you don’t want to stay stuck or give up on your new skill. The default is to fall back on your existing knowledge and habits, but those will end up being a crutch. Try out new ways to do things, or explore another language to gain some perspective.
If you’re always working in the same environment, growth can be harder to find. Stay curious and investigate when you encounter something you don’t understand. You can also take advantage of the occasion to improve your soft skills such as writing clear code and comments, or coaching another member of your team. There are many ways to learn, but you have to look for them and plan to learn instead of leaving it to chance.