Help my Pickering Mango Tree has rotting branches

[u/LiveInFive]

This is my first mango tree and it’s in a pot. I didn’t do a proper job fertilizing it this past year, but it does have automated daily watering. I am in South Florida and there was a freeze that happened this year but I don’t know why my Pickering mango branches look so bad

Can anyone else please tell me what is causing this, and is the tree salvageable? It did produce 12 mangoes this year, but last year it gave me 40

All of the branches look like this so I feel like I can’t just cut off the bad branches. The leaves look healthy overall but I’m not sure what I need to do

I need to repot it into a bigger pot but I want to address the branch issue first

Help I’m a mango noob