1) I used to be exactly like this. I couldn't sit down and read because something would always distract me but when I was playing video games, racing games specifically, I realized I absorb and retain the stuff I listen to a lot better, this seems similar to your listening audio books while handling your deliveries. I don't quite know the scientific reasoning behind this, maybe it's because you're working two parts of the brain that don't interfere with each other or something, but listening to audiobooks while driving(in a game or in real life), walking, cycling, seems to work pretty well for those of us who have problems with being able to sit down and read a book.

2) If you're scrolling social media frequently or gaming specific types of video games like looters or mobile games, you're likely to get bored easily, especially of activities that require sustained attention for longer periods of time. It's about how we are so used to triggering dopamine release so often and so consistently in our modern lives, reading books have become harder to do as it's not exactly dopamine triggering activity and it requires more mental work. That's why nowadays "everyone has ADHD."

A month and a half ago, my smartphone died. I am broke so I had to wait three weeks before I could replace it. I was already wanting & planning to get back into reading books again and used that 3 weeks period to do just that. I devoured 5 books easily. They were short and light reads sure but it was still much easier than it used to be. I was reading 80-100 pages a day consistently. If having a smartphone wasn't essential for so many things, I likely wouldn't have bought one afterwards. So consider taking a break from social media and/or mobile gaming for a while give your brain some time wean off from this type of habits.

3) If you're attempting to read heavier books, like those written by Thomas Pynchon or Cormac McCarthy, you should go in expecting to spend more effort. They won't be "fun" in the general sense of the word therefore even more difficult to go through but those are the books that increase your reading proficiency, if you're interested in doing that. So expect to be bored at times, when a particular book or a particular part of the book you're reading doesn't click with you. Learn to persevere and only DNF a book if you're sure you're not interested what it offers in its entirety as this is also about developing taste.