Sure is, I did exactly what you are planning and put the long cage 105 R7000 with the rest of my 5800 groupset so I could run the 11-34 cassette, it works smoothly.
With all that gear range I do find my chain flaps more, creating noise, especially noticeable on rougher roads. Because of this I actually wish I’d spent a little bit more and got the RX800 mech with the clutch. But the 105 still works great. And you might need a new chain for extra length too, so it does all start to add up.