Jackpot, I want to point out a very common side-play mistake that players make in your game against DonJuan. Don't worry if this doesn't make sense to you right away. Most players don't EVER figure this out. You'll get this eventually. Look in the image below. You played j7 here. This is not the correct way to play a side. The reason for this is because it allows your opponents to eventually play i8(I call this "running you up on the wall/side". This will force you to protect the NE corner, so you will be forced to play h9 after your opponent plays i8. And after you play h9, if your opponent is smart, they will play h8(I call this "finishing with the Sweep"). This is where your opponent will Gain Tempo. And now you will have to move again.
But what's worse is, now you will have an Unbalanced Edge(UE) on the North side of the board. So, there is going to be an empty space at that g10 spot. So, what this means is, it means if you get the NW corner, your opponent can now Wedge in at that g10 spot and get their own corner at k6(the NE corner). And now what's worse is, now your opponent can WORK FROM that NE corner. Make sense?
So... what we want to look for when we are playing a side is... we don't want to have 2 pieces exposed like h8 and i8 are in the image above after you made your move, because it allows our opponent to "Run you up on the wall, and finish with a sweep". h1 is a perfectly acceptable way to play a side in the image above and so is j1 if you would have had a move there because you can't be forced into a UE, at least not one that can't be balanced back out later. This is difficult to explain so don't worry if you make this mistake a few more times. It took my brother at least 6 months I think to get this right.
Also, d3 would have been a very good move for you here because it would have given you a Closed 2 on that bottom side. A Closed 2 means that you have control of a side by having the 2 pieces in the middle and the pieces on both sides of you are empty. Closed 2's are an acceptable way to play a side. The other acceptable ways are, Full 4/balanced edge, Open 2, and sharing a side is also acceptable. b7 would have also been a very good move here because you are flipping a lot of inside pieces. h8 would have also been a very good move for you here.
When we play a side, we want it to be clean. We want to make sure that we can't be forced into an Unbalanced Edge. OR, we have to make sure that we can balance our edge back out if we do so. Side-play gets very tricky. Just try to keep everything really tight and clean.
I recommend going through some of my games and looking at my side-play and if you have any questions feel free to ask. I hope this helps a little anyhow.
https://www.itsyourturn.com/pp?gm&g=...1847&t=1&gn=97
Edit... Green missed their opportunity to play i8, but you still ended up with a UE and lost that NE corner because of it.