Summary: It's an incremental process, not a "big bang", to go from college theory work to a substantial project. There is no substitute for experience.
After reading the whole question, I don't think your real question is the title of "Where and how do I search for ICs?". Instead I think your real question is more like - how can you choose components for a project, when you don't understand what components you need, and you don't understand enough of the datasheets to be confident that you are choosing suitable components.
I am a computer engineering student and started being interested in electronics for my degree thesis.
You don't say how much electronics is taught in your computer engineering course. However even though you are interested in electronics, if they aren't teaching you enough electronics for what you want to do in your thesis, then don't try to make this an electronics thesis. Instead, keep electronics as a hobby interest for now and focus on what you can do for your thesis.
As already mentioned in comments, you should consider approaches like block diagrams. That is similar to decomposition in computer programming, where you break down a system requirement into functions, data types etc.
But what if you don't know enough about which electronic components are currently available, to know what blocks in your block diagram are sensible?
You said that you...
feel that what I'm missing is a primer on...the real world or something.
Many (most?) of us went from theory to "real world" in steps by doing projects, starting with something small and getting bigger each time. I doubt that anyone went straight from theory to a (successful) big project. That experience, of making increasingly complex projects, does a few things (just like learning any new skill):
You increase your confidence for tackling more complex projects, because of each previous success.
You get to expand your knowledge of current technology with each new project. Each time you can focus on learning only what is new & different in that project, relying on your experience from previous projects for elements that are common between those projects and the new project.
This increasing knowledge helps you to know what sensible "blocks" you can include on your next project block diagram. For example, at the beginning, you might not know how to detect when a voltage is above an upper limit or below a lower limit. For that project, you do some research and find there's a term for that — window comparator — and you can add that to the list of blocks which you can include in future block diagrams.
Another important way to increase your knowledge incrementally is to read project-based books or magazines (Elektor is a current example of such a magazine - there were many others in the past, which have now disappeared) and build at least some of the projects. With each project you will learn new things, including new "blocks" (ICs, interfaces, functionality like window comparators etc.) for your future block diagrams.
A few final points, from my own experience:
Sometimes you need to allow yourself to fail, at least initially, because that is when you are likely to learn the most.
If you always do the same project type (e.g. flashing LEDs) then you will eventually be able to do them in your sleep, but you won't learn anything new. If you try something requiring different knowledge (e.g. designing a switch-mode power supply) it is more likely not to work first time. You'll learn lots from troubleshooting and fixing it, but that will take time - so don't choose a "stretch goal" project requiring new knowledge, with a hard deadline.
One example of a book which is somewhere between the "circuit design" books you already found and real world knowledge, is "Practical Electronics for Inventors" by Paul Scherz and Simon Monk. Early editions had several mistakes, and even the current latest (4th) edition has errata - but at least errata lists are available. Another example is "Practical Electronics Handbook" by Ian Sinclair and John Dutton. These books contain examples of the circuit design "building blocks" which you might find useful. You might prefer the style and contents of one book over another, so these are not specific recommendations, just examples of the type of book you might find useful.
There is always "The Art of Electronics" by Paul Horowitz and Winfield Hill. However that is heavy on theory. So while it does include some practical information, if you haven't already read this book, check to see if it is "practical enough" for you.
However, books on their own aren't enough. You have to try some projects, to find either "that was much easier than expected, so I can try something harder next time", or "oops, that is much harder than expected, I'll pick something simpler to build up my knowledge from a lower starting point".
In short: It's an incremental process, not a "big bang", to go from college theory work to a substantial project.
