As far as the second video, well first you hit the Audi by going too wide. You're fortunate they didn't hit the wall and have their race ruined because of your mistake. They shouldn't have hit you back, but that would've been the end of it. However you then left them no room going into the chicane at the bottom of the hill. It's hard to tell where the Audi was at that point because you didn't have radar on, but it looked like they were almost side by side when they made contact, so you should have left them room instead of cutting into their line. Then you also basically try to push the Audi off the track going uphill because, as you can see in the mirror, they are still somewhat beside you. It may have been unintentional on your part, but you should have left them room. Overall, your actions were not very respectful to the Audi driver.
You should always have the radar on if you're near other cars, and especially if you're trying to pass them. You were blind to where the Audi was and assumed you were ahead of them when you were not. (I'm giving you the benefit of the doubt that you didn't do all this intentionally) You didn't have the clear position and should have left room on the track. You initiated three actions which could have ruined the Audi's race. Was the Audi being too aggressive in the uphill contact? Maybe, but at that point I would've been pretty mad too.