Take it easy CyclChyk. I've never been riding with you but from what I read I'm sure you're fine. Don't be so frustrated and get out there, on the road, riding. Most road cyclists can't pick up their water bottle from the ground and have never even thought about doing that, and they are not in trouble riding on the road for so much.
Just go in a parking lot where you're nearly sure there won't be any car any time soon and play with your toy - the bike, that is.
Try stopping at a specific line, coming sort of quickly. Try only the back brake and see what happens (skidding). Then only the front - see, your weight is shifting forward, you need to brace it with your arms. Then various combinations of both brakes. You're learning things.
On another day, after a ride, go back to the parking and start circling around the intersection of two lines (parking spots dividers). Make smaller and smaller circles. Ride with the brakes on - see, you can still go forward while braking at the same time. Smaller circles again. You might fall, but it's unlikely that you'll break anything.
In two weeks, try the water bottle trick. Put the bottle at the intersection of those same two lines and see what you can do.
When you ride home, practice riding with only one hand. Try to pick up your water bottle and drink with one hand, then the next. Make sure you are on a traffic-calm street if you're insecure. If it's cool and your nose is running, try a snot rocket, they're empowering.One day you can even try riding with no hands. For one second. And then maybe more. Be sure you're in a calm area, again, and be focused.
It's not more complicated than that. There are not that many more things to learn. Ah, yes, descending. Cornering. All things you can practice by yourself in real-life situations. Track stands.
Take it easy and enjoy the ride...