If you had of pulled the plugs turned it over to get rid of water from cylinders and the changed the oil it would have likely been ok.... seen this happen a couple of times and engine was fine. Timing belt would not have let go.
But if you let it sit with water it's fubar.

2nd hand engine complete would be cheapest and easiest option.

If its an insurance job i guess its up to them how they fix it.... but again if it sits too long with water everything will be screwed possibly even the heads....so again 2nd hand complete engine would be best....

Good luck !

__________________
MY99 WRX EJ2.35L 720whp 9.48@147mph
https://youtu.be/c_lYEG0_Dyo