I was in a similar situation after finishing my Master's in Math, switching my focus from Finance to Data Science/Software Engineering and looking for my first job in tech. Although I could code and had done some small projects on my own, my knowledge of most topics in IT was very limited.

I remember I used to attend all kinds of tech meetups and feel like I don't belong, like I'd missed out something in my education compared to people with CS backgrounds. I identified especially these areas I was lacking in most: Web Development, Networking, Security, Operating Systems, Hardware, Databases

I found short courses (mostly on YouTube) on each of these topics to understand the basics. Later most of them kept appearing in my tasks at work and I dove deeper in them.

As it turned out over time, I hadn't missed out that much and now with 4 years of experience, working as SDE at Amazon I feel more knowledgeable than a majority of people with CS backgrounds.