Not being able to reverse park is quite devastating.

Turns out not only am I not good at parallel parking, but I suck with reversing and using my ORVMs in general.

So I have some questions regarding that and if I am unable to make myself clear in English (as it's my second language, so I apologise if you have trouble understanding what I am writing), you can use the photos as reference even through the photos look like they were made by a 4 year old :)

1. When reversing into a cramped parking lot where when you try to reverse into a spot you have to be mindful of the cars in front as well, how do you judge distances using your ORVMs, like how do you know that your rear bumper is aligned to the bumper of the car which is occupying the parking lot next to where you want to turn to. Here's a photo, in this how do we know that the rear left of the blue car is aligned with the front left of the car number 2 using ORVM? I can't gauge distances using ORVM so any idea?
2. So when you are reversing into the parking lot, there is a chance that you haven't done it right and the rear mid (or the rear left or the rear right) of your car is about to hit the parked car, how do we judge that distance provided we don't have a camera and the hood of the parked car is not visible through the IRVM and the rear windshied.. Here's a photo, in this how do we know that rear mid, rear left, or the rear right of the car is about to hit the parked car, that is, how do we know whether it's about to hit the parked car 1?
3. Even when we have cameras and when we're reversing how do we know whether the corner of the car is going to scrape through the parked car where we're reversing and how do we actually gauge that distance through the ORVM? Here's a photo, how do even with camera we realise that it's not going to hit the car parked 1, like how do we realise that how far away the blue car is from the car 1 when it's parked using the ORVM?

These are some of my questions, sorry to put you through these absolutely atrocious and childish drawings but this is how I could've actually explained what I was trying to as I am not a native speaker, as you've seen a lot of my questions are about judging how much is the distance between the rear of the car and the object using ORVM but no matter how much I practice when I look into the ORVM, I have no idea how far the car actually is, it's like mirror somehow removed depth, I can't judge the distances as I could when I look from the ORVM.

I would be grateful if somebody could take the time to answer this, it has been really bugging me, I genuinely appreciate any and all advices that you guys have to give.

Edit: Guys this is the kind of parking lot I am talking about. And also, as I talked about earlier how do I gauge the distances using ORVM?

Edit2: People have suggested here to make an angle before starting to reverse first, my question is at what point do I know that I should go for an angle such that when I reverse the car, the car ends up in between the two cars, how do I judge that?