Alternative for 12V supply to short-circuit NTC bypass after a few seconds?
One alternative is to add a series resistance, which you then bypass after a few cycles. This gives enough time for the field inside the transformer to build up, and to fill the input capacitors. You short this resistor after a certain amount of time and continue normal operation.

Like this:



Don't be alarmed by current spikes at the end, they are under 15A effective and should not trigger a fuse.

This circuit shows an application where you generate a rectified DC voltage. the current spikes are due to the capacitor being charged. The same voltage is then used to control a relay which triggers at 300V to bypass the input resistor.

Forget the thermistor. You will still have to wait for it to cool down if you cycle things fast.

Biduleohm suggested a nice link. There is also the circuit that uses the principle I suggested: Series resistors solution

You can find many good circuits there, the engineering is solid.

What is your application?