It does sound like something blew.
So basically no power to the small solenoid wire terminal.
Are you able to run a temporary feed to test it on the car like I mentioned.
As it went suddenly unlikely to be ignition switch , but you may be able to test for a voltage there when turning the key to start position.
Slightly in a different direction some time ago I bought a Fiat Grande Punto 1.3 MJ apart from other issues it had no power to the starter circuit and also the fuel pump in the tank. Long story short there was no power to the relay in the fusebox under the bonnet, you may be able to test at that point and either try a different relay or with a fused link bridge that relay to see if it powers up the starter circuit.
On this vehicle the trigger wire to the relay had rotted through inside it's plastic sheaf a few mm from the ECU on the opposite inner wing.