>>96453025
If you are not able to declare attack for whatever reason (can't suspend, suspended, can't attack players/Digimon) you can't begin Progress.
If you can declare an attack (Sec-1), progress activates and the Digimon becomes immune to all effects until any End of Attack effects resolve.

If it is targeted by a lingering effect during that attack (DP-, Sec-1) that effect applies again once the attack is over. So if you get Sec-1 and then evolve to Omnimon, you no longer have Progress so can't attack for game.