If your serve improves your game will improve greatly. You should try to work on that backhand of yours, try getting someone to feed you balls their or use a ball machine. If i really need to work on my backhand, in warmup i will sometimes run around my forehand and hit an inside out backhand just to really warm it up. My 1hbh is kind of a liability for me as well, clearly the weaker of my strengths. Which would be crushing flat FH, BH slice, serve, and dropshots. Another tip that helped me greatly would be to study your opponents game, this is what all good players do. During your warmup just feed him balls in different areas of the court and see how he plays them. Usually if you hit down the middle you will realize which side they favor, FH/BH, normally it will be FH so then you alter depth and spin. You might not get this technical the first couple times but just try to study their mishits and weaker shots, so that you may use it against them. You'll find you will be playing smarter tennis, the satisfaction of working your opponents weakness which you exploited is a wonderful feeling. You have potential especially on your FH cross court, remember you can build your game on your strengths but shouldnt be dependent on it. I would suggest doing some of this until your backhand gets better, at least againts better players.
-Also i just watched your video again, your footwork needs work. You are standing around sometimes doing nothing, you get into position on time but barely, when you come up against harder hitters and angles you need to move quicker. Keep your feet moving, this also plays into building somewhat of your game on your forehand, if you move quicker you can hit inside out forehands as opposed to having to play a backhand.