Skiing a new PB is always rewarding. Congrats! And behind a "new driver" too. Good skiing.
Watched your video numerous times and saw many very positive aspects to your skiing. If you can work on the following, there is no doubt you will get into 28 if not run it.
1. Slower turn in for the gate. Your first movement is "back" and quick. Slowly build angle and lean and maintain balance over both feet.
2. Going to 1,3, 5 (off side) tendency is to ski to buoy then turn. Ski as wide as you can away from the boat and buoy. Keep ski going outbound to maintain space.
3. If you look at your off side, you grab the handle at the buoy even before the turn is complete. Part of that is due to being narrow as you come out of the turn. As soon as you grab the handle, that is the end of gaining additional angle out of the turn as you have already applied pressure of the rope. Again, ski wide, complete the turn, establish your angle then "ride the line" to the other side.
4. You exit the turns with an initally good position, but particularly going into the white water from your off side turn, you come up and pull in your arms. (from the looks of the wake, you are skiing a 1990-1996 Nautique hull, so the wake can be a bit larger than new boats, but keep your weight over the ski and keep your edge all the way through the second wake and you will be wide.
You have a good foundation and the desire to improve. With some tweaks and additional work, your buoy count will increase.
These are just my observations and I am sure other ballers will have even greater insight.
Again, congrats on the new PB and best wishes for a Merry Christmas and a great New Year.