The EFL needs to show that they've got something about them and save up any and all penalties for when they come back down, no matter how many more years it takes. That would put the cat amongst the pigeons. Even better, levy a stiff financial penalty in lieu of a points deduction (and I mean stiff, say above half of what they earn from going up as a starting point) and say that if it's not paid within a season of promotion they'll be refused access to the EFL should they ever be relegated. That cash can be distributed equally amongst all clubs in the three EFL divisions who turned a profit in the previous season.
While I agree with you that it would be welcome to see the EFL try and actually enforce its own rules and laws in a robust way, or to introduce some form of ruling (though clubs have to agree it) to encourage clubs to actually operate solvent, I've got to play devils advocate too. The EFL have been petrified of a PL2 breakaway. So I can understand their reticence to rattle the cage of clubs who they fear would leave their membership and with it most likely break their whole pyramid. I wish that wasn't the case, but its not that difficult to imagine such a scenario where some of the bigger clubs from the EFL walk.
I understand the sentiments behind applying it to the following season, if they aren't relegated. Teams are generally dragged into a relegation battle, if they aren't in one already, upon entering administration, but what if a team missed out on the play-offs because of a points deduction, and then had to start the following season on -12? I'd be annoyed if that happened to us.
Automatic embargo for 2 seasons, only way forward for me. EFL oversee selling of players the Summer offence is confirmed and then Players only allowed to sign within that 2 year period after EFL have confirmed it keeps them within the FFP. That will hurt a club far more than points.