My amateur observations, if you want to hit a harder ball (e.g. trying to hit an aggressive shot for a winner, putting away a sitter/short ball, etc...)
- Current stance too open to really get pace, close stance a bit more, slightly closer to neutral
- More intensity please. Move. Explode. Hit through, not just spin.
- Hit more in front of your body, less to the side, you're reaching out too far to the right to make contact
- Attack the ball, take it earlier more in front and get your weight into it
Some examples here (both righties and lefties)
I don't know if this is what you're going for or not (video of you hitting a metre behind the service line). It's not a rally ball, but I just thought it might be something you can add for matchplay when you get the opportunity to really let one rip.
Here's a clip of Gulbis practicing something similar (a bit oldschool and he doesn't catch the racquet in match/point play)