The biggest take away is that once you have the skills, you can work with any tools. Better tools just make it easier. Work on learning how to cook, it sounds like you have some basic cookware that can probably work for many things.
For example, I have extensive cookware, in cast iron and stainless. A few inexpensive non-stick aluminum too. I’ve had anodized aluminum.
They all cook a little different, but I could probably make most of my 300+ recipes in any of them (stuff with rubber handles can’t go in the oven). It would just take a little re-thinking to work around how each pan/pot works.
I can brown on non-stick, and even develop fond (which is tricky).
As other have said, your best bang-for-the-buck will be inexpensive sets or cast iron. Keep in mind that inexpensive non-stick is trickier to work with (mostly because the pans are thin, so controlling heat is harder), and they wear out faster than better cookware. I’ve replaced quite a few over the years.
After decades of cooking and trying the “latest fad”, I lean heavily toward stainless, but only a few brands. There’s a lot of crap stainless out there, selling cheap… And in this case you get what you pay for.
These folks did some good research on stainless, and explain the difference more concisely than I can. Their research comports with a lot of other reviews and docs I’ve read over the years - I’ve even cooked with some of these brands, like the Cuisinart (which I own), the Tramontina (which I’ve gifted), and also a brand not listed - Heston (which is quite expensive, but really nice). My experience is they all cooked the same, which is to say they heat surprisingly quickly, hold heat well (similar to cast iron, though not as much thermal mass), make browning a snap, and require surprisingly lower burner settings than even good anodized aluminum.
Plus stainless is a breeze to clean - a quick deglaze and everything comes right out. I’d even argue it can run through the dishwasher (though it may dull a little, it’ll cook the same).
To come full circle, look for easy, one-dish recipes as a great place to start.
I think both America’s Test Kitchen/Cooks Country and Good Eats are great places to start to learn how to cook. ATK/Cooks Country has a bunch of recipes, and they design them to be simpler than what you’d find in something like The Joy of Cooking, while explaining how they changed a recipe or process. Good Eats is great for learning how’s and why’s, what’s going on when doing certain things - Alton is big on visualizing the chemistry and process of cooking.
One downside to no microwave for a single person is reheating leftovers becomes more challenging. Lots of dishes, especially casserole/stews, etc, reheat very readily in a microwave. Which reduces your cooking effort - you can make a pot of stuff, throw it in the fridge and have it for dinner tomorrow too. I do this, even freezing portions so I can have it next week (so I don’t get bored eating the same thing 3 days in a row).
Edit: find an inexpensive 4 quart pot to add to your collection. It’s a very useful size - great for boiling water for pasta, potatoes, etc.