Sometimes the level difference is too great. He hits harder than you do on both wings, serves faster and spinnier AND with better placement, hits higher quality shots (more spin/longer/faster), returns better, finds better angles... Yeah, gonna be difficult. :lol: It's not bad to admit that he's much better than you are.
I see you're trying to hit a bit longer even when pressured. It doesn't work bad, but your shots lacks either good enough placement, either pace/spin to really hurt. Good neutralizing shots in short, but they do not hurt or pressure your opponent. Each time you are not able to hit long enough or/and without enough pace, you are consistently punished. Either you have to hit in the last 6' of the court consistently (18' between baseline and service line!) which you cannot at the moment being, either you have to give an harder to deal with ball.
You have to rework your FH seriously. You're really limited in spin, and acceleration capacity on your FH wing. You hit often too late, you lack consistency. It often results on fluff balls, they bounce high but lack the heaviness that would make those balls harder to deal with.
About your BH... you're still punished on that wing due to short balls and lower pace. Work on hitting with better placement. And please, engage your shoulders inside the shot. Hit while moving your body weight forward. You're only using your arms, you're not going to have any pace like that. Move your body inside the shot, move your body weight forward.
Compared to his, your serves sit up in the middle of the box, waiting to be smacked. Big no-no. And these are your first serves(!), not good news at all. Not good enough placement or spin to be threatening, let alone pace. You really have to hit with much better placement, the middle of the box serve won't do at higher level. The pace isn't important here, you can fold your radar gun. Your placement is at fault.
Tl;Dr:
1) He's better than you are;
2) Work on your groundstrokes technically speaking, use your body and core muscles more than before, you're only using your arms;
3) Your serve lacks placement.
EDIT: Look at DiGiulio in the video you link. Look at how much he tries to move his body weight forward. How much he tries to use his core muscles to hit the ball. How he coils and uncoils. That's what you lack. That's where you loose pace and hitting power.