Water damage repair on solders

So this is the cicuit for a 1h0257j VolksWagen polo vacum pump for central lock. I got it for practice since it was replaced.
The question the problematic part seems to be a burned soldering, it is just a bridge but since the water damage made it more and more isolated and at the end gave in. So, how do i liquidate the burnt solder? Tryed heating it but it didn’t do anything and can’t heat it further without damaging the board itself.
On a side note i removed the legs of the connector since most some of it was burnt too (mainly the power suply slots) but i can’t seem to be able to soak up the damaged solder, i used striped (new and clean) cooper wire. I tryed to add some flux thats what the shiny part is, the burnt part around the already liquified solder are just the is oxid i could’t remove from it with alcohol and brush on the first run.