I am sure that in the fullness of time NATO will have to seriously rethink its doctrines. Although there is little accurate information in the public domain about the air war in Ukraine, it would appear the Russians took out AD radars and airfields fairly early on.
Based upon this the F35B might seem a good idea, but only if you plan to operate it out of the woods in a similar manor to the old RAFG Harrier force. I'm not sure how resilient it would be in that environment.
So back to the title of this thread...........Harrier GR9 cost £21.5m each. F35B cost £92m.