Coolant leaking

BGTV8

You need to be sure that the original problem did not result in a damaged head gasket.

If the accident damage caused coolant loss and the engine overheated to the extent that a head gasket was damaged, you are now getting exhaust gas into the cooling circuit and this is pressuring the coolant and forcing coolant out of the overflow.

You can test the coolant for the presence of combustion gases (actually carbon monoxide).

You really need to rule this out before going much further.

Bottom line is that this issue (if it is failed head gasket) can be traced directly back to the accident damage AND ought to be covered by your insurance and/or repair warranty.

First order of business is to establish whether you have a simple leak issue OR failed ehad gasket which is pressurising the coolant circuit.