My main thought is that you were generally too defensive and passive. In a handicap game, Black has to use his initial advantage to attack. Try to separate White into small pieces, don’t let him build strength and build strength yourself while attacking. White should be the defending player, not Black. For instance:
move 10 is big but passive, doesn’t threaten anything.
moves 28-36: how many points did Black gain by crawling like that? In exchange, White built a very strong wall which is more valuable.
move 40 is big endgame but doesn’t threaten anything, White is already out in the center so is not in danger. A move around K5 (border of two moyos) was perhaps better.
move 42 was passive. Playing at O16 (push and cut) would be more active.
Thank you for your insights, Yes i figured after the game that i let white grow too big especially on the left side. On the lower left corner i misread the cutting points with the B2 move, maybe playing C2 was better but gote. Also i think the joseki option on the upper left corner was not good for black, but i have trouble deciphering what was better… maybe playing D17 instead of E17 or even G16… or maybe approaching from the other side of the corner but it was riskier.
The handicap system’s goal is to give both players - of an unequal strength - the same chance of winning a game. If you play passive - by playing defensive moves - you hand over the initiative to your opponent, who will be happy to take the big points and secure easily much more territory than you do.
If the midfield seki wouldn’t have happened, you could have lost by at least a 100 points. For a 3 stone handicap against a 7kyu and a 4 kyu, that is enormous.
So don’t let the game be dictated but try to pressure your opponent into unhealthy shapes, etc. Fight more and run away less.