>You can't jihad on an empty stomach.
They did it during the battle of Khandaq. And our Prophet (peace be upon him) said "My sustenance is under the shade of my spear." So since when have non muslim governments become ar-Razzaaq? Since when do the believers put their reliance on them?
>Restoring Khilafah is not possible these days
So possible that it's inevitable. Who do you think needs convincing? The masses of Muslims already want the Khilafah, and the kings and dictators and their stubborn lackeys will never accept it, unless they repent. What you said as a condition is already the case. And isn't fighting a kind of Da'wah? One will find that actions are more convincing than words.
There are many locations one can go to perform Jihad for the sake of Allah, from Africa to Sham to the far lands of Arakan and the Philippines. But why would you go through that trouble to join the Taliban's forces? Only because their power is consolidated? Why shouldn't a Muslim who is eager to fight for Allah's cause go and join one of the Wilayat?