He encouraged his supporters to protest at the capital, perfectly legal. He didn't tell them to invade it. They got carried away and should be punished for any laws they violated.
Trump deserves impeachment and disqualification from ever holding any federal office for his actions, taken while in office, over the course of months leading to the insurrection at the Capitol. Impeachment is not an indictment for a criminal charge. Whether his conduct was illegal is an entirely separate and immaterial consideration. He violated his oath of office and his duty and responsibilities to the country in ways that are neither forgettable or forgivable.
You're focusing on specific instructions to invade the Capitol which is completely irrelevant. The House articles of impeachment do NOT charge that Trump
instructed the mob of domestic terrorists to invade the Capitol. You're confusing instruction with incitement. Trump's responsibility for fomenting and inciting the insurrection that occurred is clear due to his persistent repetition of a lie, over
months, that a failure to be re-elected could only occur if the election was stolen by massive widespread fraud. He told citizens that democracy and the Constitution were under assault and being taken away from them and they must act and fight to protect and preserve the nation. By doing so, he provided the fuel, ignition, and direction of a fire of fear, without any concern over the manner or intensity with which it would burn and which consequently led to the assault on the Capitol and terrorizing of the legislators inside.
The perpetrators of the violent acts of domestic terrorism and insurrection should pay the legal price for their actions. Trump should pay the political price of impeachment and disqualification from holding any future federal office for his actions.