Review request 12k game

In move 108 black cuts at G6 on move 108 and analyze mode shows that being the turning point of the game. Can anyone walk me through why? I looked at the lines that analyze mode proposed and playing F6 does seem to cut in to the space white gets on the left, but of course at the expense of allowing the H5 group to live.

Any thoughts or anaysis welcome!

You mean Move 109. Black loses winrate so severely exactly because of what White showed, that Black can be forced to capture three stones tightly at the expense of valuable forcing moves by White. The reason rhe siruation seems at all murky is because White’s exchange F4 for G3 is bad and unnecessarily reduces the liberties of his stones.

As bugcat mentioned, while you captured 3 stones, the opponent ended up expanding more territory, so it’s net negative for you

Did a quick review, you lost around 4 points in that exchange on just territory, you also removed any weaknesses in white shape that could easily be worth even more than that.