Look... I really want you to do this, but do think - at this stage - you should not be on the road. If you can't work out automatically that turning the steering wheel does 'this' or 'that' when reversing, you are going to reverse into someone or damage another car.
You are so against more lessons, why? There are all sorts of instructors out there for people like you and you should not be driving until you can happily enter a carpark, drive into a space, and reverse out.
I knew someone a v long time ago, who would never turn right. i.e. if on an ordinary road and she had to position herself to turn right, indicating, and either cars banked up behind her or the road was wide enough for cars to go round.... she just would not do it. She kept driving around to avoid right turns. Ridiculous but true!
OP, it's not just you, you have to think of other drivers. Impatient ones for instance. A lot of drivers are impatient and you not being able to reverse out of a space is going to make them even more impatient, and worse for you.
Seriously think about more lessons, you should not be driving around when you can't park anywhere.