1. If you do it a lot, you get better at it.
2. Cook in bulk -- I make all lunches for the week at once (mostly salads with a protein). Slow cook a big piece of meat almost every week, and if not, roast a chicken or something like that. Almost every dinner I make is for at least 2 (maybe 3) meals. I freeze if I'm sick of it.
3. If you are just starting, it's ok to start with easy things that are more ready-made (as long as you have to do something). The habit you want is preparing rather than going out or delivery. Gradually increase the difficulty as you can handle it.
To answer your specific question, stove, oven, slow cooker. If you do it, having a good knife and pans is nice.
For one person; sometimes for my young son too.
I cook everyday. I cook from scratch mostly. I consider myself a competent by low-skill cook. I can follow a recipe and it normally works; I can bake bread, cakes, cookies and they all work well.
Microwave or slow cooker are most common (I have managed to drastically reduce my energy use); all in one on an electric hob (I'd prefer gas hob) and rarely in the electric oven.
I'd like to cook in bulk and then freeze the food but I have a big fridge and tiny freezer which is frustrating and sub-optimal.
If I need something cooked quickly, I can cook chicken thighs in a pressure cooker in about 10-15 minutes with a sauce. On the other hand if I am working a long day and I don't want a steak for dinner, I can put it in the sous vide machine and not worry about it.
The third most used item for me probably would be a wok.
Friday is usually "date night" although we have been married for 8+ years. We both work from home so lunch every weekday.
We have a range with an oven plus we have a separate convection oven. We have a microwave but we just use it for melting butter and as a kitchen timer.
We usually do 2 vegan meals a week. The rest protein and vegetables as I am diabetic. We stay away from soda, sugar, processed foods as much as we possibly can.
As cheesy as it sounds, the George Foreman Grill has become essential - I roast nuts and garlic on it for salad, cook salmon burgers and veggie burgers plus buns and onions for them, cook fish steaks or fillets - way quicker than the stove or oven, and it is true that the fat and grease just run off.
Eggs mostly :), eating for gains!
Most of what I cook is on the stove top. Pan searing meat, boiling rice/veggies.
Mostly using the oven, and the last months I've focused on long time cooking on low heat which is really tasty
3 times a day, mostly stove and oven. Microwave if I'm too impatient to wait for vegetables.
Just a electric stove, plus dreams of a larger kitchen...
We have a range cooker.